text:
Talk:GRU (Russian Federation)

Untitled
I have never seen such a fuc... up article on such an important intelligence organization as GRU. Do yourself a favor - Translate http://ru.wikipedia.org, or https://pl.wikipedia.org/wiki/GRU  or other f.. horror. — Preceding unsigned comment added by 69.112.5.131 (talk) 17:44, 7 November 2013 (UTC)
 * And, was it, ... the participation of the GRU in the sinking of the "Kursk 141".
 * Hello respected admirals, officers, and, sailors. Closing the rescue hatch. From the outside of the side. Or, GRU combat swimmers? Or, the divers of the FSB? Further . Who can guess? What did the FSB officers foil the temporary anti-hydrogen catalysts? All the ends are shod with these bastards. Boyfriends of the US CIA. Well, a CIA agent who participated in the action they ... where to Deli?109.134.133.241 (talk) 08:57, 27 August 2018 (UTC)

The article needs changes
It needs them badly. Common style of the article isn't neutrile and antirussian. There are alot of definatly antirussian sources like different defectors and others such peopels, there are alot of unprooven phrases from politicians, that looks more like populism, then well-weighted statements. This should be cleaned out. Even references list in the end begins with GRUs defectors and so on - I don't think this is correct, as it's not GRUs purpose. Oleg_Str

Rewrite sentence
Could someone rewrite the following sentence: During its history, the GRU was always a subordinate to the NKVD, its successors (KGB, etc.), the GRU has at different times, made very spectacular recruits of foreign agents, and was the first Soviet intelligence service, to exploit the lax security of western companies, and began to steal S&T (Science and technology) though this later became a domain controlled by KGB, under line x, later Directorate T. It's a long, run-on sentence and I can't make heads nor tails of it. Abigail 16:25, May 14, 2004 (UTC)

 * how's this:
 * During the entire period it operated, GRU was always subordinate to the NKVD and its successors (KGB, etc.). The GRU was particularly successful in recruiting foreign agents, and was the first Soviet intelligence service to exploit the lax security of western companies.  GRU agents pioneered espionage targeted at gaining science and technology (S&T) material.  This function later fell to the KGB, under its "line x" (later Directorate T).
 * -- Finlay McWalter | Talk 01:17, 21 May 2004 (UTC)

Article rename
Any objection to an article rename to the full name? To be more consistent with other Russian articles. -Joseph 04:24, 2004 Sep 4 (UTC)

 * The renaming is wrong. The abbreviation GRU is well known, the full name is not so. — Monedula 20:59, 4 Sep 2004 (UTC).

Holy Similarities Batman!

Was the symbol of the GRU spetsnaz later adapted into Batman's symbol? The two are pretty much identical. I scanned through Batman's article, and nothing of the sort was listed under "Costume."
 * Your title for this section made me laugh. First I thought they had nicked the Batman logo, but it's the other way around. The spanish version of this article has a similar logo. AFAIK, this logo is the real one. I think its supposed to represent a bird overlooking the world, not a bat.--81.105.251.160 22:38, 22 July 2006 (UTC)

 * But yeah my first impression of seeing that symbol was like: BATMAN. Lol, guess those of us living in the West have a pretty different POV on that bat-looking symbol. :P 24.80.236.14 (talk) 23:20, 13 July 2009 (UTC)

NOT emblem of GRU
The emblem pictured on this page is NOT that of GRU. Along the bottom is does in fact say, in Russian, "Military intelligence," but along the top the acronym is "VS RF." I'm not sure what "VS" means, but "RF" certainly means "Russian Federation" ("Rossiiskaia federatsiia" in Russian). In other words, this emblem might be that of a post-Soviet successor organization, but it is NOT that of the Soviet-era GRU. Terrasirradient 16:00, 12 December 2006 (UTC)

This (see the second image) seems to imply that the logo (if not the GRU name) is still in current use. Lionfire 01:28, 14 December 2006 (UTC)

 * It's correct for the current GRU. VS RF is Armed Forces of the Russian Federation (perhaps better sense is Military Forces of the Russian Federation). Buckshot06 14:29, 22 September 2007 (UTC)

Deletion of text
Vlad Fedorov deleted the following large portions of text:

During 2006 Georgian-Russian espionage controversy several GRU officers were accused by Georgian authorities of preparations to commit sabotage and terrorist acts. GRU detachments from Chechnya were transferred to Lebanon independently on the United Nations Interim Force in Lebanon after 2006 Israel-Lebanon conflict "to improve Russia’s image in the Arab world", according to Sergei Ivanov. Zelimkhan Yandarbiyev was assassinated by two GRU officers. GRU officers are accused of creating criminal death squads Special services are making teams for extrajudicial punishment (Russian)] by Igor Korolkov, Novaya Gazeta, January 11, 2007. It was reported that GRU helped Saddam Hussein to hide his Weapons of mass destruction before US invasion of Iraq in 2003 Russia Hid Saddam's WMDs -by Ion Mihai Pacepa, Washington Times, October 2, 2003.

This text was supported by references and relevant to the subject. Therefore, I had to restore it. ~

Iraq/ WMD
I read both articles that are referenced as supporting the claim, that the GRU cleaned Iraq of WMD's before the 2003 Invasion- but both of articles are mere speculation and there is not one official source or some documents that they are based on. Also, both were published in the Washington Times and that is as if Wikipedia would rely solely on Fox News for its political articles. Therefore i removed the sentence until some proof backs this claim up. ~

Reply (GRU and Saddam's WMD)
Russia "Cleaned Up" Saddam's WMD

Former Deputy Undersecretary of Defense John A. Shaw, a "top Pentagon official who was responsible for tracking Saddam Hussein's weapons programs before and after the 2003 liberation of Iraq," stated in October 2004, March 2005, and again in February 2006 that it was the Russians who helped Saddam Hussein to "clean up" his weapons of mass destruction stockpiles "to prevent the United States from discovering them."

In late October 2004, the International Atomic Energy Agency (IAEA), the United Nations' "nuclear watchdog", told the UN Security Council that the Iraqi Interim Government "reported to the agency" that approximately 380 tons of "conventional explosives" were "missing" from the "vast" Al Qa Qaa complex of "1,100 buildings" about 30 miles south of Baghdad "after last year's invasion."

IAEA Director-General Mohamed ElBaradei "passed on the letter from Iraqi authorities informing the agency of the theft." The IAEA said that "the material, sealed and monitored by its inspectors until the US-led invasion, had gone missing some time after" April 9, 2003, "during 'the theft and looting of governmental installations'." The IAEA "last inspected the munitions at al-Qaqaa in January 2003 but [had] not been allowed back into Iraq" following the invasion.

The Associated Press reported October 25, 2004, that, "At the Pentagon, an official who monitors developments in Iraq said U.S.-led coalition troops had searched Al-Qaqaa in the immediate aftermath of the March 2003 invasion and confirmed that the explosives, under IAEA seal since 1991, were intact. Thereafter, the site was not secured by U.S. forces, the official said, also speaking on condition of anonymity."

The Pentagon was "unclear" as to whether or not the explosives had "disappeared" after the site in Iraq "fell under US control."

On February 18, 2006, Shaw "told an audience" at "a privately sponsored 'Intelligence Summit'" in Alexandria, Virginia, that "The short answer to the question of where the WMD Saddam bought from the Russians went was that they went" to Syria and the Bekka valley in Lebanon, Kenneth R. Timmerman reported February 19, 2006, in NewsMax. "They were moved by Russian Spetsnaz (special forces) units out of uniform, that were specifically sent to Iraq to move the weaponry and eradicate any evidence of its existence," Shaw said.

However, the Financial Times (UK) reported October 28, 2004, that Shaw had "not provided evidence for his claims and the Pentagon [had] distanced itself from his remarks."

On December 10, 2004, Bill Gertz reported in The Washington Times that Shaw, who was a former aide to Secretary of Defense Donald H. Rumsfeld, "was forced to leave his position ... as the result of a 'reorganization' that eliminated his job, defense officials said. ... Shaw said he had been asked to resign for 'exceeding his authority' in disclosing the information, a charge he called 'specious'."

It was reported that GRU helped Saddam Hussein to hide his weapons of mass destruction before the US invasion of Iraq in 2003

Merge with Spetsnaz GRU
there isn't enough info/structure about the Spetsnaz GRU to warrant a separate article. Lugnuthemvar (talk) 09:35, 3 March 2014 (UTC)

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GRU building
Please provide WP:RS telling that buildings on the image are indeed GRU headquarters. In addition, this looks like a TV screenshot. Is it? If so, this is a copyright violation. My very best wishes (talk) 18:36, 1 September 2016 (UTC) Некоторые юные участники Википедия пишут и пишут о секретной работе Военной Разведки России. И, здесь важны мотивы. Зачем ? Почему ? Для чего ? Ну, естественно, чтобы помочь ! Улутшить ! И страничьку Википедия о Военной Разведки России. И, работу доблестных защитников  Отчизны. Честно разделить оплату и почести за успешные ОП. Часть ,и, весомая часть,  пологается  их друзьям и компаньёнам  из дружественных  Организаций. Ведь наши офицеры нехотят  всё себе заграбастать, а ? Pro Rolex2 (talk) 13:42, 13 September 2016 (UTC)
 * "Some of the young participants of Wikipedia write and write about the secret work of the Russian military intelligence. And there are important reasons. What for ? Why? For what ? Well, of course, to help! To improve! And page Wikipedia about Russian military intelligence. And the work of the valiant defenders of the Motherland. Honestly split payment and honors for successful OP. Part, and a significant part of, relies on their friends and on friendly organizations. After all, our officers reluctantly everything yourself hog" --Pro Rolex2 (talk) 13:42, 13 September 2016 (UTC)
 * Maybe lost in translation, but I don't know what you are talking about. The picture looks like the same building on google street view, but google images are copyright and someone added that picture as free license to be used for wikipedia. here's a link to a (copyright) internet image  --IP_commenter (talk) 04:34, 14 September 2016 (UTC)
 * No, we don't know that it's free even if the uploader has claimed it as their own. Thousands upon thousands of copyrighted images are uploaded by users to Wiki Commons and claimed as their own. I've found the originals of enough photos used in articles on Wikipedia from there that have simply been cropped slightly and passed off as 'own work'. The uploader -(here - is highly dubious. Of the 3 images s/he has ever uploaded (all in a short spate in 2013), one was quickly deleted as a copyright violation. If there was exif data, I might have been more predisposed to believe that it was genuinely that person's work. Wiki Commons has to look out for WP:COPYVIO. As editors here, we have to be even more vigilant as we are providing a venue to accommodate a high risk copyvio photo at Wikipedia's risk (i.e., by posting it, we are validating it as being a genuinely free image). That's not a risk we are at liberty to take. --Iryna Harpy (talk) 00:18, 15 September 2016 (UTC)
 * You have an issue: in your edit summary you seem to claim that the image is original research yet here you seem to claim that the image is a copyright violation and this contradicts your claim that it is original research i.e. it cannot be original and copied at the same time. Unless you are the legal copyright holder (or authorized representative, (or have rights as licensee)) YOU HAVE NO LEGAL RIGHT TO HAVE THE IMAGE REMOVED. --IP_commenter (talk) 19:43, 20 September 2016 (UTC)

Many Wikipedia languages other than English use this image. ☆ Bri (talk) 23:54, 24 March 2018 (UTC)

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Dissolved in 1992 or not? Zombie spy agency? The living dead?
"In May 1992 the GRU was dissolved and became part of the new Russian Ministry of Defense. In 2006 the GRU moved to a new Headquarters complex at Khoroshovskoye Shosse.." These consecutive sentences seem to say that it was dissolved in May 1992, meaning that it no longer existed but that its existence continued 14 years later. Should it say that in May 1992 it was transferred fro one supervising authority to another, or should it say that it was dissolved in May 1992 and then it was restored to function at some later date? Perhaps we could just leave out "was dissolved and" so that the article says ""In May 1992 the GRU became part of the new Russian Ministry of Defense." Edison (talk) 14:56, 14 July 2017 (UTC)

Section needed on 2016 US election
Needs complete section. Wikipietime (talk) 21:15, 14 July 2017 (UTC)

Regarding the proposal of the President of Russia
The President has reorganized military intelligence. Just as with the KGB already happened. Since he has encountered some incompronesance ... Everyone has his arguments ...Simpoatisant1234567890987654323456 (talk) 14:02, 24 October 2017 (UTC)

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Soviet vs. Russian
The GRU that this article is about only came into existence in 1992, as part of the Russian Federation. If we're going to be including information on individuals like Klaus Fuchs, then I think either the primary infobox needs to be changed, or we need a new article making a distinction between the Soviet and post-Soviet organizations, akin to the SVR vs. the KGB. PvOberstein (talk) 17:43, 8 April 2018 (UTC)

Pronunciation
Is there an official way to pronounce "GRU"? I always thought each letter was pronounced individually (mostly based on TV), like FBI, but recently other people have argued with me that it's more like SEAL or SOCOM. Whatever the case, if there is a definitive correct way to pronounce it, then it would be helpful to have it written phonetically in the introduction of the article. --Trifler (talk) 09:02, 19 August 2018 (UTC)
 * Ambiguous abriviature.

Some of GU Colonel's feel kind of hunted. Even though. User's Wikipedia.org. That is sufficiently cultured. Highly intelligent content of internet users. All of them. Often and and long. In the academic, professorial Ciber society. Wikipedia online incyclopedia. Sensitive natures. No less diplomatic. As one of the most diplomatic diplomats. According to the M.G.I.M.O .. For Wikipedia user's. Administrators and Authors. Not required - an order, a decree, an order to be given. To get them to write a new topic. Develop or improve an old, forgotten topic. Expression of interest is sufficient. Public interest. Or ... administrative interests. State administration. Even more ! Civilian political leadership of the Russian Federation. First. Mr. President of the Russian Federation. Wladimir Putin. And also. Minister of Foreign Affairs, Mr Lavrov. And ... the Minister of Health. Mr. Michail Albertowitsch Muraschko. Shown a real interest. How can it be reduced ?! Political influence. Political force! At home and abroad. On the part of a Sicret Agenci, (state, military) administration. Under the pseudonym GU Russia. Military command of the Armed Forces of the Russian Federation. Defense Minister. College of the Headquarters of the High Command. Manifested. All natural. Economic interest. To add. Foreign exchange holdings, savings, avuars. From "the state in the state in the state" (GU Russia). On the budget of the Ministry of Defense of Russia. The knowledgeable user of Wikipedia. The employment contract with GU was not signed. Should she request a written order? To help. Contribute. Of course not! This is a matter of conscience, honor, likes and dislikes. From Wikipedia users. Who has signed a general contractor? Yes, perhaps.
 * Colonel! We are loyal to the Secretary of Defense and the President. And you ?195.244.164.66 (talk) 15:48, 21 September 2021 (UTC)

Added new source

 * Story by Daniel Turovsky, translation by Kevin Rothrock. November 6, 2018, What is the GRU? Who gets recruited to be a spy? Why are they exposed so often? Here are the most important things you should know about Russia’s intelligence community, Meduza.

Infinitepeace (talk) 04:35, 12 January 2021 (UTC)
 * Pension Fund of the Officers of the Headquarters of the Supreme Command. Is it true? That the colonels of the GU / GRU are officers of the Headquarters of the Supreme High Command. User3456789876 (talk) 14:11, 24 August 2021 (UTC)

Requested move 15 April 2021

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: Moved to GRU (Russian Federation) and GRU (Soviet Union). (non-admin closure)  Vpab15 (talk) 14:36, 23 April 2021 (UTC)

– Both of the current titles are pretty messy and don't really fit with the article titles policy. With regard to this page, it's title is just a collection of essentially meaningless letters that definitely don't satisfy common name. Meanwhile, "Main Intelligence Directorate (GRU)" is equivalent to if Federal Protective Service (Russia) was instead titled "Federal Protective Service (FSO)", meaning it isn't made clear by the title that that GRU article is only about the Soviet GRU. Thanks in advance, RadiculousJ (talk) 05:21, 15 April 2021 (UTC) The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
 * GRU (G.U.) → Main Intelligence Directorate (Russia)
 * Main Intelligence Directorate (GRU) → Main Intelligence Directorate (Soviet Union)
 * Oppose: Indeed, these are currently not the best names, but a Google Books Ngram chart shows how much more often reliable sources call this organization GRU. The respective articles should be moved to GRU (Soviet Union) and GRU (Russia) or GRU (Russian Federation). —Michael Z. 13:20, 15 April 2021 (UTC)
 * Oppose move to 'Main Intelligence Directorate (Russia)'. Though I support a move to 'GRU (Russia)' or similar. —blindlynx (talk) 13:49, 15 April 2021 (UTC)
 * Changing support to GRU (Russian Federation) and GRU (Soviet Union), based on Michael Z's n-grams. RadiculousJ (talk) 18:45, 15 April 2021 (UTC)
 * Support move. Any title such as GRU (G.U.), GRU (Soviet Union) or GRU (Russia) automatically fails WP:ACROTITLE, part of the article titles policy, ("Acronyms should be used in a page name if the subject is known primarily by its abbreviation and that abbreviation is primarily associated with the subject") which can't be overriden by a local consensus. (t · c)  buidhe  07:19, 22 April 2021 (UTC)
 * Support GRU (Russian Federation) and GRU (Soviet Union). Very definitely the common name. Nobody calls it the Main Intelligence Directorate. -- Necrothesp (talk) 10:39, 22 April 2021 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion: Participate in the deletion discussion at the. —Community Tech bot (talk) 14:53, 16 October 2022 (UTC)
 * Spetsnaz gru 1999.jpg

 * Many problems.
 * But, there is also good news.
 * Colonel Victor Boat released from US prison.
 * Kalabaha1969 Zweite (talk) 16:30, 16 January 2023 (UTC)

Requested move 18 April 2023

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: not moved. (closed by non-admin page mover) – robertsky (talk) 12:51, 25 April 2023 (UTC)

GRU (Russian Federation) → GRU – no page should redirect to the page with the same name with brackets. ErceÇamurOfficial (talk) 12:30, 18 April 2023 (UTC)

 * Oh. curprev 21:15, 2 April 2023 UtherSRG talk contribs 85 bytes +85  UtherSRG moved page GRU to GRU (Russian Federation): Revert undiscussed move (WP:RMUM): Requested by 162 etc. at WP:RM/TR: Moved without discussion; GRU (Russian Federation) is the consensus title per a 2021 RM thank Tag: New redirect
 * GRU (disambiguation) In ictu oculi (talk) 14:15, 18 April 2023 (UTC)
 * GRU (Russian Federation), Russian intelligence service
 * GRU (Soviet Union), Soviet military intelligence service

 * Leaning to oppose given that the article is split. In ictu oculi (talk) 14:16, 18 April 2023 (UTC)
 * Oppose, and redirect GRU to Gru (disambiguation). There is no primary topic, given that GRU (Russian Federation) and GRU (Soviet Union) both have significant long-term notability. 162 etc. (talk) 15:39, 18 April 2023 (UTC)
 * I already redirected GRU to Gru (disambiguation) before reading this comment since that was the previous status quo prior to an undiscussed move that went against the consensus of the previous discussion. Makes sense anyways: Turns out that the incoming links to GRU are split between referring to GRU (Soviet Union) and GRU (Russian Federation). Steel1943  (talk) 20:35, 20 April 2023 (UTC)
 * I'll note that this will require a significant amount of link fixing. 162 etc. (talk) 01:27, 21 April 2023 (UTC)
 * Yep, realized that hours ago. Steel1943  (talk) 16:46, 21 April 2023 (UTC)
 * Oppose. This agency’s real name isn’t even GRU, while the Soviet one’s was. —Michael Z. 13:49, 19 April 2023 (UTC)

 * Oppose per previous consensus. As mentioned above, the WP:COMMONNAME for this article's subject may not even be "GRU". Steel1943  (talk) 20:32, 20 April 2023 (UTC)
 * Oppose per User:162 etc. (both have long-term significance), consensus, the 2021 RM and the lack of any argument for the move. Llew Mawr (talk) 11:13, 21 April 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

"Glavnoe Razvedyvatel'noe Upravlenie" listed at Redirects for discussion
The redirect [//en.wikipedia.org/w/index.php?title=Glavnoe_Razvedyvatel%27noe_Upravlenie&redirect=no Glavnoe Razvedyvatel'noe Upravlenie] has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached. Steel1943 (talk) 20:10, 21 April 2023 (UTC)

"Razvedupr" listed at Redirects for discussion
The redirect [//en.wikipedia.org/w/index.php?title=Razvedupr&redirect=no Razvedupr] has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached. Steel1943 (talk) 20:16, 21 April 2023 (UTC)
 * New dimension. Along with the renaming to GU. Changes in... features. Management and Control in the Army and Navy. Management, not discovery, of information - as a priority. The officers of the GU at the staff of the Supreme High Command of the Armed Forces of the Russian Federation are no longer required. To hide or to cover / shield oneself intensively. On the contrary, to act / administer / control openly. (If not already public.) That should add more respect and recognition.
 * GU, this is GOV. - Administration !
 * Not a military department for scouting info.Steel1943 Zweite (talk) 15:50, 7 June 2023 (UTC)

title: Talk:GRU (Russian Federation)


text:
Ridgway's hawk

Ridgway's hawk (Buteo ridgwayi) is a bird of prey in the family Accipitridae endemic to the island of Hispaniola (both Haiti and the Dominican Republic) in the Caribbean. It is classified as Critically Endangered because of habitat destruction and human persecution in the Dominican Republic; however, due to conservation efforts, the population is now increasing.

It is named in honour of the ornithologist Robert Ridgway.

Description
B. ridgwayi is a medium-sized, compact hawk, measuring 36–41 cm long. The adult has brown-grey upperparts and greyish barred underparts, with a reddish-brown wash, rufous-tinged thighs, and a black-and-white barred tail. The male is greyer than the female, and the legs and the base of bill are yellow.

Diet and breeding
Ridgway's hawk feeds on rodents, bats, centipedes, birds, anoles, skinks, frogs, and snakes. It nests in the crowns of tall trees, such as Roystonea borinquena, with nest-building in December through June, and egg-laying in January to June. The clutch size is 1 to 3 eggs. Most pairs raise 1 to 2 young, though 3 have been reported.

Distribution
Ridgway's hawk's original breeding range included all of the island of Hispaniola and some of the adjacent isles and keys, such as Gonâve Island, Île-à-Vache, Tortuga, Beata Island, and Alto Velo Island. However, it has since been extirpated from a large area of the Dominican Republic and almost all of Haiti, due to extensive deforestation and loss of habitat there. It was thought to be completely extirpated from all of Haiti; however, recent expeditions to the islands of Les Cayemites discovered a breeding population there. In the Dominican Republic, the only known surviving populations outside of reintroductions is in and around Los Haitises National Park, and a relict population in the Samaná Peninsula.

Conservation
This bird is described as critically endangered, due to clearance of its forest habitat and persecution by local farmers, who claim that the species preys upon their domestic fowl. Conservationists have countered that poultry is nothing more than a minor element of their diet, and that the Ridgway's hawk has a highly varied prey base, with reptiles comprising up to 90% of its diet. Electrocution from power poles and nestling parasitism by Philornis pici flies are also reasons for population decline. Reintroductions in the Ecological Center of the Puntacana Resort and Club in La Altagracia Province have proven successful; 25 individuals were also released in Aniana Vargas National Park in Sánchez Ramírez Province, with more releases planned. It is proposed that a "Ridgway's Hawk Day" should become a national holiday in the Dominican Republic, in order for the species to become more publicly known and protected.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Ridgway's hawk


text:
Talk:Great Train Wreck of 1918

Requested move
Great train wreck of 1918 → Great Train Wreck of 1918 Page move to comply with Wikipedia naming conventions: namely, caps for proper nouns — Splintercellguy 18:47, 6 Jun 2005 (UTC)
 * Weak Oppose. Although I am unsure as to whether the names of rail disasters are considered proper nouns, the convention on Wikipedia seems to be to keep them lowercase. See List of rail accidents for numerous examples. Convention on the web in general seems to be divided. Can anyone shed more light on whether or not this should be capitalized? Kaldari 19:59, 6 Jun 2005 (UTC)
 * Weak oppose. If you google train wreck of 1918 nashville, there doesn't really seem to be much consensus as to a single name for the event (many of the 'great train wreck of 1918' hits are Wikipedia mirrors)--EG "Great Nashville Train Wreck of 1918" "worst US train wreck, Nashville, Tenn." "1918 July 9, Nashville, Tenn., Train wreck". Makes it seem like they are all more descriptive names than 'proper' ones. Niteowlneils 16:07, 10 Jun 2005 (UTC)
 * Oppose It seems to be a simple noun phrase rather than a proper noun, although I could be convinced otherwise.  —Michael Z. 2005-06-17 04:52 Z

Dutchman's Grade vs. Dutchman's Curve
Contemporary sources say that the accident occured at "Dutchman's Grade" while modern sources seem to prefer "Dutchman's Curve". I don't suppose it matters much which one we use, but I thought I'd make a note of it anyway. Kaldari 19:01, 14 July 2006 (UTC)

Aftermath section - deleted paragraph
I deleted this:

 * "Yet because the NC&StL, like all U.S. railroads at the time, was being run by the government under the United States Railroad Administration during World War I, government officials had changed the railroad's former passenger train schedules. In the past these two trains would have met safely far to the west of Nashville later in the morning.  But because of the changing of the timetables, these two trains now met somewhere, depending on timing, nearer to Nashville where the possibility for mistakes was more likely.  The USRA put, in essence, a gag order on the news of this wreck to try to play down public fears of having the U.S. government run the country's railroads.  The Hammond Circus Train Wreck, another serious accident involving a circus train, had happened the previous month under the USRA's watch.  The ICC failed to note the changes in scheduling that the USRA had wrought nor did they consider the effect those changes might have had as a contributing factor to this wreck."

 * In fact, if Train No. 1 had been on time, the two trains would not have met at that point. The contention that there was a USRA cover-up is not supported by any references - the references include do include contemporary news reports. — Preceding unsigned comment added by 82.44.90.249 (talk • contribs) 02:06 6 April 2011 (UTC)

 * I undid this before I noticed the above, since there was no edit summary. I tried to reedit it to make it less WP:POV, but gave up, and removed it again.  I think that there are some facts that could be restored, but probably not in the Aftermath section. Tim PF (talk) 12:10, 6 April 2011 (UTC)

Controversy of Train Wreck
I have an original document from a researcher in Moscow, Russia that documents the disappearance of Allen H Stuber who was a ICRR engineer (began career in 1904). They report his disappearance on July 4th, and the opinion from two sources was that he "knew too much" about the train wreck event. This suggests that the event was intentional because of the knowledge of the event before it actually occurred. There is an implied linkage to story which involved the gunpowder factory workers in connection with the Memphis 4th of July event at East End Park. This information was conveyed by a relative of Allen H Stuber who witnessed. Mapsurfer49 (talk) 23:00, 30 October 2012 (UTC)
 * Can you upload the document to Wikimedia Commons? I know someone who would be interested in following-up on this. Kaldari (talk) 01:15, 31 October 2012 (UTC)
 * I am reluctant about uploading this document to Wiki Commons because it contains genealogy data who family members are still alive. I'd prefer to send as email attachment to you or whomever is doing the research.  Mapsurfer49 (talk) 21:13, 7 November 2012 (UTC)

title: Talk:Great Train Wreck of 1918


text:
Template talk:CBM computers

Regarding C65 and other 'Secret Weapons of Commodore'
I removed the entry for the C65 on the grounds that, if we were to include all unreleased CBM products (which we should if including the C65 in the first place), I think the list would become unfeasably big (and confusing). But we should of course make sure the C65 and others is clearly visible in the Commodore Int'l article, perhaps under their own heading ("Unreleased products"?). --Wernher 16:31, 14 May 2004 (UTC)

title: Template talk:CBM computers


text:
Fédération Aéronautique Internationale

The Fédération aéronautique internationale (FAI; World Air Sports Federation) is the world governing body for air sports, and also stewards definitions regarding human spaceflight. It was founded on 14 October 1905, and is headquartered in Lausanne, Switzerland. It maintains world records for aeronautical activities, including ballooning, aeromodeling, and unmanned aerial vehicles (drones), as well as flights into space.

History
The FAI was founded at a conference held in Paris 12–14 October 1905, which was organized following a resolution passed by the Olympic Congress held in Brussels on 10 June 1905 calling for the creation of an Association "to regulate the sport of flying, ... the various aviation meetings and advance the science and sport of Aeronautics." The conference was attended by representatives from 8 countries: Belgium (Aéro Club Royal de Belgique, founded 1901), France (Aéro-Club de France, 1898), Germany (Deutscher Luftschiffer Verband aka "German Airship League", founded 1902), Great Britain (Royal Aero Club, 1901), Italy (Aero Club d'Italia, 1904), Spain (Real Aero Club de España, 1905), Switzerland (Aero-Club der Schweiz, 1900) and the United States (Aero Club of America, 1905).

On 2 February 2017 the FAI announced its new strategic partnership with international asset management firm Noosphere Ventures. FAI Secretary General Susanne Schödel, FAI President Frits Brink and Noosphere Ventures Managing Partner Max Polyakov signed the agreement, making Noosphere Ventures FAI's Global Technical Partner.

The FAI suspended Russia and Belarus due to the 2022 Russian invasion of Ukraine, as a result of which pilots from Russia and Belarus will not be able to compete in any FAI-sanctioned event in the 13 FAI air sports disciplines, including paragliding, hang gliding, and paramotoring.

FAI General Conference
The 117th FAI General Conference took place in Dayton, Ohio, US (the 'Birthplace of Aviation') on 26 and 27 October 2023.

The 118th FAI General Conference will be held from 20 to 21 November 2024 in Riyadh, Saudi Arabia.

Sports
13 Sports:
 * 1) Aeromodelling (modelling (space modulation) – Space Modelling)
 * 2) Amateur-Built & Experimental Aircraft
 * 3) Ballooning
 * 4) Drones
 * 5) General Aviation
 * 6) Gliding
 * 7) Hang Gliding
 * 8) Microlights and Paramotors
 * 9) Paragliding
 * 10) Powered and glider aircraft Aerobatics
 * 11) Rotorcraft
 * 12) Parachuting (Skydiving)
 * 13) Space

Air Sport Commissions

 * 1) General Air Sports (CASI)
 * 2) Aerobatics (CIVA)
 * 3) Aeromodelling (CIAM)
 * 4) Amateur-Built and Experimental Aircraft (CIACA)
 * 5) Astronautic Records (ICARE)
 * 6) Ballooning (CIA)
 * 7) General Aviation (GAC)
 * 8) Gliding (IGC)
 * 9) Hang Gliding and Paragliding (CIVL)
 * 10) Microlight and Paramotor (CIMA)
 * 11) Rotorcraft (CIG)
 * 12) Skydiving (ISC)

Events

 * World Air Games
 * World Paragliding Championships
 * World Gliding Championships
 * World Parachuting Championships
 * FAI World Aerobatic Championships
 * World Hot Air Ballooning Championships
 * FAI World Paramotor Slalom Championships
 * 2023 FAI F3P World Championships
 * World Cup of Indoor Skydiving
 * FAI World Grand Prix
 * Red Bull Air Race World Championship
 * Parachuting (Skydiving)

All the events sanctioned by the FAI are listed in the events calendar.

World Championships

The first World Championships in a certain class took place in the following years:

 * 1) 1951: F1A, F1B, F1C
 * 2) 1960: F2A, F2B, F2C, F3A
 * 3) 1961: F1D
 * 4) 1970: F4B, F4C
 * 5) 1972: S-classes
 * 6) 1977: F3B
 * 7) 1978: F2D
 * 8) 1985: F3C, F3D
 * 9) 1986: F3E (now: F5B)
 * 10) 1989: F1E
 * 11) 1994: F5D (now F3E)
 * 12) 1998: F3
 * 13) 2010: F6A (WAG)
 * 14) 2010: F6B (WAG)
 * 15) 2010: F6D (WAG)
 * 16) 2011: F3K
 * 17) 2012: F3F
 * 18) 2013: F3N
 * 19) 2013: F3P
 * 20) 2014: F4H
 * 21) 2018: F3U
 * 22) 2019: F5J
 * 23) 2024: F3M

Activities
The FAI is the international governing body for the following activities:
 * Aerobatics through the FAI Aerobatics Commission (Commission Internationale de Voltige Aérienne – CIVA)
 * Aeromodeling and drones through the FAI Aeromodelling Commission (Commission Internationale d'Aéro-Modélisme – CIAM)
 * Ballooning through the FAI Ballooning Commission (Commission Internationale de l'Aérostation – CIA)
 * General aviation through the FAI General Aviation Commission (General Aviation Commission – GAC)
 * Gliding through the FAI Gliding Commission (International Gliding Commission – IGC)
 * Hang gliding & Paragliding through the FAI Hang Gliding & Paragliding Commission (Commission Internationale de Vol Libre – CIVL)
 * Human-powered aircraft through the FAI Amateur-Built and Experimental Aircraft Commission (Commission Internationale des Aéronefs de Construction Amateur – CIACA)
 * Microlighting and Paramotoring through the FAI Microlight & Paramotor Commission (Commission Internationale de Microaviation – CIMA)
 * Skydiving through the FAI International Skydiving Commission
 * Rotorcraft through the FAI Rotorcraft Commission (Commission Internationale de giraviation – CIG)

The FAI establishes the standards for records in the activities. Where these are air sports, the FAI also oversees international competitions at world and continental levels, and also organizes the World Air Games and FAI World Grand Prix.

The FAI organises the FAI International Drones Conference and Expo. This event offers a platform for organisations, businesses and individuals to discuss how drones are used today and to create a framework for how they will be used and impact on life in the future.

The FAI also keeps records set in human spaceflight, through the FAI Astronautic Records Commission (International Astronautic Records Commission – ICARE)

Kármán Line definition
The FAI defines the limit between Earth's atmosphere and outer space, the so-called Karman Line, as the altitude of 100 km above Earth's sea level.

Records
Among the FAI's responsibilities are the verification of record-breaking flights. For a flight to be registered as a "World Record," it has to comply with the FAI's strict rules, which include a proviso that the record must exceed the previous record by a certain percentage. Since the late 1930s, military aircraft have dominated some classes of record for powered aircraft such as speed, distance, payload, and height, though other classes are regularly claimed by civilians.

Some records are claimed by countries as their own, even though their achievements fail to meet FAI standards. These claims are not typically granted the status of official records. For example, Yuri Gagarin earned recognition for the first manned spaceflight, despite failing to meet FAI requirements. The FAI initially did not recognize the achievement because he did not land in his Vostok spacecraft (he ejected from it), but later it recognized that Gagarin was the first human to fly into space. The FAI then established the Yuri A. Gagarin Gold Medal, which has been awarded since 1968.

Classes
The following types of craft have records:
 * Class A Free Balloons
 * Class B Airships
 * Class C Aeroplanes
 * Class CS Solar-Powered Aeroplanes
 * Class D Gliders & Motorgliders
 * Class E Rotorcraft
 * Class F Model Aircraft
 * Class F1 – Free flight
 * Class F2 – Control line
 * Class F3 – Radio control
 * F3K – Discus Launch Glider
 * F3F – Slope Soaring
 * Class F4 – Scale model aircraft
 * Class F5 – Electrically powered model aircraft
 * F5B – Electric powered motor gliders
 * F5D – Electric powered pylon racing model aircraft
 * Class F8 – Autonomous flight (created by CIAM in 2006, later retired)
 * Class F9 – Drone Sports
 * F9A – Drone soccer
 * F9U – Drone racing
 * Class G Parachuting
 * Class H Vertical Take-off and Landing (VTOL) Aeroplanes
 * Class I Manpowered aircraft
 * Class K Spacecraft
 * Class M Tilt-Wing/Tilt Engine Aircraft
 * Class N Short Take-off and Landing (STOL) Aeroplanes
 * Class O Hang Gliding & Paragliding
 * Class P Aerospacecraft
 * Class R Microlights and Paramotors
 * Class S Space Models (Model rockets)
 * Class U Unmanned aerial vehicles

Awards
The FAI Gold Air Medal was established in 1924 and was first awarded in 1925. It is reserved for those who have contributed greatly to the development of aeronautics by their activities, work, achievements, initiative or devotion to the cause of Aviation. The FAI has also awarded the Paul Tissandier Diploma since 1952 to those who have served the cause of aviation in general and sporting aviation in particular.

The FAI also makes awards for each of the following air sports.

 * Awards for Ballooning:
 * The Montgolfier Ballooning Diploma
 * The Santos Dumont Gold Airship Medal
 * Awards for General Aviation:
 * The Charles Lindbergh General Aviation Diploma
 * Awards for Gliding:
 * The Lilienthal Gliding Medal
 * The Pelagia Majewska Gliding Medal
 * The Pirat Gehriger Diploma
 * Awards for Rotorcraft:
 * The FAI Gold Rotorcraft Medal
 * Awards for Parachuting:
 * The FAI Gold Parachuting Medal
 * The Leonardo da Vinci Parachuting Diploma
 * The Faust Vrancic Medal
 * Awards for Aeromodelling:
 * The FAI Aeromodelling Gold Medal
 * The Andrei Tupolev Aeromodelling Medal
 * The Alphonse Penaud Aeromodelling Diploma
 * The Antonov Aeromodelling Diploma
 * The Andrei Tupolev Aeromodelling Diploma
 * The Frank Ehling Diploma
 * Awards for Aerobatics:
 * The Leon Biancotto Aerobatics Diploma
 * Awards for Astronautics:
 * The Yuri A. Gagarin Gold Medal
 * The V.M. Komarov Diploma
 * The Korolev Diploma
 * The Odyssey Diploma
 * Awards for Hang Gliding:
 * The Pepe Lopes Medal
 * The FAI Hang Gliding Diploma
 * Awards for Microlight Aviation:
 * The Colibri Diploma
 * The Ann Welch Diploma
 * Awards for Aviation and Space Education:
 * The Nile Gold Medal
 * Awards for Amateur-Built Aircraft:
 * The Phoenix Diploma
 * The Phoenix Group Diploma
 * The Henri Mignet Diploma

FAI Young Artists Contest
The FAI Young Artists Contest is an international painting competition for youngsters between the ages of 6 and 17. Each FAI Member Country organises the contest in their country, and the national winners are submitted to the International Jury each year.

title: Fédération Aéronautique Internationale


text:
António Lobo Antunes

António Lobo Antunes (born 1 September 1942) is a Portuguese novelist and retired medical doctor. He has been named as a contender for the Nobel Prize in Literature. He has been awarded the 2000 Austrian State Prize, the 2003 Ovid Prize, the 2005 Jerusalem Prize, the 2007 Camões Prize, and the 2008 Juan Rulfo Prize.

Life and career
António Lobo Antunes was born in Lisbon as the eldest of six sons of João Alfredo de Figueiredo Lobo Antunes (born 1915), prominent Neurologist and professor, close collaborator of Egas Moniz, Nobel Prize of physiology, and wife Maria Margarida Machado de Almeida Lima (born 1917). He is the brother of João Lobo Antunes and Manuel Lobo Antunes.

At the age of seven, he decided to be a writer, but when he was 16, his father sent him to the medical school of the University of Lisbon. He graduated as a medical doctor, later specializing in psychiatry. During this time he never stopped writing.

By the end of his education, Lobo Antunes had to serve with the Portuguese Army to take part in the Portuguese Colonial War (1961–1974). In a military hospital in Angola, he became interested in the subjects of death and "the other."

Lobo Antunes came back from Africa in 1973. The Angolan War of Independence was the subject of many of his novels. He worked for many months in Germany and Belgium.

In 1979, Lobo Antunes published his first novel, Memória de Elefante (Elephant's Memory), in which he told the story of his separation. Due to the success of his first novel, Lobo Antunes decided to devote his evenings to writing. He has been practising psychiatry as well, mainly at the outpatients' unit at the Hospital Miguel Bombarda of Lisbon.

His style is considered to be very dense, heavily influenced by William Faulkner and Louis-Ferdinand Céline, and his books also tend to be on the long side.

He has published more than twenty novels, among the most important are Fado Alexandrino (1983), As Naus (1988) and O Manual dos Inquisidores (1996). His works have been translated into more than thirty languages.

He writes a biweekly newspaper column for Visão, a Portuguese magazine.

He was granted the Grand Cross of the Order of Saint James of the Sword.

Personal life
He married his first wife Maria José Xavier da Fonseca e Costa (1946–1999), the second of three daughters of José Hermano da Costa and his wife Clara da Conceição de Barros Xavier da Fonseca e Costa, by whom he has two daughters: Maria José Lobo Antunes in 1971 and Joana Lobo Antunes in 1973. They were divorced.

His second wife (whom he also divorced) was Maria João Espírito Santo Bustorff Silva (born Lisbon, 13 August 1950), daughter of António Sérgio Carneiro Bustorff Silva and wife Ana Maria da Anunciação de Fátima de Morais Sarmento Cohen do Espírito Santo Silva, by whom she has one daughter: Maria Isabel Bustorff Lobo Antunes (born 1983).

He was married for the third time in 2010 to Cristina Ferreira de Almeida, daughter of João Carlos Ferreira de Almeida (Lisbon, 1941 – 2008) and wife Natércia Ribeiro da Silva.

Awards

 * Prize of Portuguese Writers' Association (1985 and 1999)
 * France Culture Prize (1996 and 1997)
 * Rosalía de Castro Prize (1999)
 * The Austrian State Prize for European Literature (2000)
 * Ovid Prize, Romania (2003)
 * Latin Union International Prize (2003)
 * Jerusalem Prize (2005)
 * Camões Prize (2007)
 * Juan Rulfo Premio de Literatura en Lengua Romances (2008)
 * France Commandeur de l'Ordre des Arts et des Lettres (2008)
 * International Nonino Prize (2014)

Non-canonical works
Published works considered non-canonical by the author himself.

 * A História do hidroavião (1994) illustrated by Vitorino
 * Letrinhas das Cantigas (Limited Edition 2002)

 * D'este viver aqui neste papel descripto: cartas da guerra ("Cartas da Guerra") (2005) - This book is the collection of war letters written by Lobo Antunes, while on military duties in Angola, to his then-wife. They were reorganized by their daughters, with no intervention whatsoever from the author for this publication. The 2016 film Letters from War directed by Ivo M. Ferreira is based on the letter collection.

title: António Lobo Antunes


text:
Diving bell

A diving bell is a rigid chamber used to transport divers from the surface to depth and back in open water, usually for the purpose of performing underwater work. The most common types are the open-bottomed wet bell and the closed bell, which can maintain an internal pressure greater than the external ambient. Diving bells are usually suspended by a cable, and lifted and lowered by a winch from a surface support platform. Unlike a submersible, the diving bell is not designed to move under the control of its occupants, or to operate independently of its launch and recovery system.

The wet bell is a structure with an airtight chamber which is open to the water at the bottom, that is lowered underwater to operate as a base or a means of transport for a small number of divers. Air is trapped inside the bell by pressure of the water at the interface. These were the first type of diving chamber, and are still in use in modified form.

The closed bell is a pressure vessel for human occupation, which may be used for bounce diving or saturation diving, with access to the water through a hatch at the bottom. The hatch is sealed before ascent to retain internal pressure. At the surface, this type of bell can lock on to a hyperbaric chamber where the divers live under saturation or are decompressed. The bell is mated with the chamber system via the bottom hatchway or a side hatchway, and the trunking in between is pressurized to enable the divers to transfer through to the chamber under pressure. In saturation diving the bell is merely the ride to and from the job, and the chamber system is the living quarters. If the dive is relatively short (a bounce dive), decompression can be done in the bell in exactly the same way it would be done in the chamber.

A third type is the rescue bell, used for the rescue of personnel from sunk submarines which have maintained structural integrity. These bells may operate at atmospheric internal pressure and must withstand the ambient water pressure.

History
The diving bell is one of the earliest types of equipment for underwater work and exploration. Its use was first described by Aristotle in the 4th century BC: "they enable the divers to respire equally well by letting down a cauldron, for this does not fill with water, but retains the air, for it is forced straight down into the water." Recurring legends about Alexander the Great (including some versions of the Alexander Romance ) tell he explored the sea in some closed vessel, lowered from his ships. Their origin is hard to determine, but some of the earliest dated works are from the early Middle Ages. In 1535, Guglielmo de Lorena created and tested his own diving bell to explore a sunken vessel in a lake near Rome. De Lorena's diving bell only had space for enough oxygen for a few minutes however, the air in his diving bell was reported to last for one to two hours with the limiting factor being a diver's ability to withstand cold and fatigue, not lack of oxygen. The mechanism he used needed to keep the pressure inside the bell continuous, supply fresh air, and remove air exhaled by the diver. To accomplish this, it is believed that de Lorena used a method similar to what would later be Edmond Halley's 1691 design.

In 1616, Franz Kessler designed an improved diving bell, making the bell reach the diver's ankles, and adding windows and a ballast to the bottom. This design no longer needed to be tethered to the surface, but it is unclear whether or not it was actually built.

In 1642, John Winthrop reported one Edward Bendall building two large wooden barrels, weighted with lead and open at their bottoms, to salvage a ship Mary Rose which had exploded and sunk, blocking the harbor of Charlestown, Boston. Bendall undertook the work on condition that he be awarded all the value of the salvage should he succeed in unblocking the harbor, or half the value he could salvage if he could not.

In 1658, Albrecht von Treileben was permitted to salvage the warship Vasa, which sank in Stockholm harbor on its maiden voyage in 1628. Between 1663 and 1665 von Treileben's divers were successful in raising most of the cannon, working from a diving bell.

A diving bell is mentioned in the 1663 Ballad of Gresham College (stanza 16):

In late 1686, Sir William Phipps convinced investors to fund an expedition to what is now Haiti and the Dominican Republic to find sunken treasure, despite the location of the shipwreck being based entirely on rumor and speculation. In January 1687, Phipps found the wreck of the Spanish galleon Nuestra Señora de la Concepción off the coast of Santo Domingo. Some sources say they used an inverted container for the salvage operation while others say the crew was assisted by Indian divers in the shallow waters. The operation lasted from February to April 1687 during which time they salvaged jewels, some gold and 30 tons of silver which, at the time, was worth over £200,000.

In 1689, Denis Papin suggested that the pressure and fresh air inside a diving bell could be maintained by a force pump or bellows. Engineer John Smeaton utilized this concept in 1789.

In 1691, Dr. Edmond Halley completed plans for a diving bell capable of remaining submerged for extended periods of time, and fitted with a window for the purpose of undersea exploration. In Halley's design, atmosphere is replenished by sending weighted barrels of air down from the surface.

In 1775, Charles Spalding, an Edinburgh confectioner, improved on Halley's design by adding a system of balance-weights to ease the raising and lowering of the bell, along with a series of ropes for signaling the surface crew. Spalding and his nephew, Ebenezer Watson, later suffocated off the coast of Dublin in 1783 doing salvage work in a diving bell of Spalding's design.

Mechanics
The bell is lowered into the water by cables from a crane, gantry or A-frame attached to a floating platform or shore structure. The bell is ballasted so as to remain upright in the water and to be negatively buoyant, so that it will sink even when full of air.

Hoses, supplied by gas compressors or banks of high pressure storage cylinders at the surface, provide breathing gas to the bell, serving two functions:
 * Fresh gas is available for breathing by the occupants.
 * Volume reduction of the air in an open bell due to increasing hydrostatic pressure as the bell is lowered is compensated. Adding pressurized gas ensures that the gas space within the bell remains at constant volume as the bell descends in the water. Otherwise the bell would partially fill with water as the gas was compressed.

The physics of the diving bell applies also to an underwater habitat equipped with a moon pool, which is like a diving bell enlarged to the size of a room or two, and with the water–air interface at the bottom confined to a section rather than forming the entire bottom of the structure.

Wet bell
A wet bell, or open bell, is a platform for lowering and lifting divers to and from the underwater workplace, which has an air filled space, open at the bottom, where the divers can stand or sit with their heads out of the water. The air space is at ambient pressure at all times, so there are no great pressure differences, and the greatest structural loads are usually self weight and the buoyancy of the air space. A fairly heavy ballast is often required to counteract the buoyancy of the airspace, and this is usually set low at the bottom of the bell, which helps with stability. The base of the bell is usually a grating or deck which the divers can stand on, and folding seats may be fitted for the divers' comfort during ascent, as in-water decompression may be long. Other equipment that is carried on the bell includes cylinders with the emergency gas supply, and racks or boxes for tools and equipment to be used on the job. There may be a tackle for hoisting and supporting a disabled diver so that their head projects into the air space.

Type 1 wet bell
The type 1 wet bell does not have an umbilical supplying the bell, because diver's umbilicals supply the divers directly from the surface, similar to a diving stage. Divers deploying from a type 1 bell will exit on the opposite side to where the umbilicals enter the bell so that the umbilicals pass through the bell and the divers can find their way back to the bell at all times by following the umbilical. Bailout from a type 1 bell is done by exiting the bell on the side that the umbilicals enter the bell so they no longer pass through the bell, leaving the divers free to surface.

Type 2 wet bell
A gas panel inside the bell is supplied by the bell umbilical and the emergency gas cylinders, and supplies the divers' umbilicals and sometimes BIBS sets. There will be racks to hang the divers' excursion umbilicals, which for this application must not be buoyant. Abandonment of a type 2 wet bell requires the divers to manage their own umbilicals as they ascend along a remaining connection to the surface.

Operation of a wet bell
The bell with divers on board is deployed from the working platform (usually a vessel) by a crane, davit, or other mechanism with a man-rated winch. The bell is lowered into the water and to the working depth at a rate recommended by the decompression schedule, and which allows the divers to equalize comfortably. Wet bells with an air space will have the air space topped up as the bell descends and the air is compressed by increasing hydrostatic pressure. The air will also be refreshed as required to keep the carbon dioxide level acceptable to the occupants. The oxygen content is also replenished, but this is not the limiting factor, as the oxygen partial pressure will be higher than in surface air due to the depth.

When the bell is raised, the pressure will drop and excess air due to expansion will automatically spill under the edges. If the divers are breathing from the bell airspace at the time, it may need to be vented with additional air to maintain a low carbon dioxide level. The decrease in pressure is proportional to the depth as the airspace is at ambient pressure, and the ascent must be conducted according to the planned decompression schedule appropriate to the depth and duration of the diving operation.

Closed bell
A closed, or dry, bell, also known as a personnel transfer capsule or submersible decompression chamber, is a pressure vessel for human occupation which is lowered into the sea to the workplace, equalised in pressure to the environment, and opened to allow the divers in and out. These functional requirements dictate the structure and arrangement. The internal pressure requires a strong structure, and a sphere or spherically ended cylinder is most efficient for this purpose. When the bell is underwater, it must be possible for the occupants to get in or out without flooding the interior. This requires a pressure hatch at the bottom. The requirement that the bell reliably retain its internal pressure when the external pressure is lowered dictates that the hatch open inward, so that internal pressure will hold it closed. The bell is lowered through the water to working depth, so must be negatively buoyant. This may require additional ballast, which may be attached by a system that can be released from inside the bell in an emergency, without losing pressure, to allow the bell to float back to the surface.

Locking onto a deck decompression chamber or saturation system at the surface is possible either from the bottom or the side. Using the bell bottom hatch for this purpose has the advantage of only needing one hatch, and the disadvantage of having to lift the bell up and place it over a vertical entry to the chamber. A bell used in this way may be called a personnel transfer capsule. If decompression is done inside the bell, it may be referred to as a submersible decompression chamber.

The bell bottom hatch must be wide enough for a large diver fully kitted with appropriate bailout cylinders, to get in and out without undue difficulty, and it can not be closed while the diver is outside as the umbilical is tended through the hatch by the bellman. It must also be possible for the bellman to lift the working diver in through the hatch if he is unconscious, and close the hatch after him, so that the bell can be sealed and pressurised for the ascent. A lifting tackle is usually fitted inside the bell for this purpose, and the bell may be partially flooded to assist the procedure.

The internal space must be large enough for a fully kitted diver and bellman (the stand-by diver responsible for manning the bell while the working diver is locked out) to sit, and for their umbilicals to be stowed neatly on racks, and the hatch to be opened inwards while they are inside. Anything bigger will make the bell heavier than it really needs to be, so all equipment that does not need to be inside is mounted outside. This includes a framework to support the ancillary equipment and protect the bell from impact and snagging on obstacles, and the emergency gas and power supplies, which are usually racked around the framework. The emergency gas supply (EGS) is connected via manifolds to the internal gas panel. The part of the framework that keeps the lower hatch off the bottom is called the bell stage. It may be removable, which can facilitate connection to a vertical access chamber lock. The bell umbilical is connected to the bell via through hull fittings (hull penetrations), which must withstand all operating pressures without leaking. The internal gas panel connects to the hull penetrations and the diver's umbilicals. The umbilicals will carry main breathing gas supply, a communications cable, a pneumofathometer hose, hot water supply for suit heating, power for helmet mounted lights, and possibly gas reclaim hose and video cable. The bell umbilical will usually also carry a power cable for internal and external bell lighting. Hydraulic power lines for tools do not have to pass into the interior of the bell as they will never be used there, and tools can also be stored outside. There may be an emergency through-water communications system with a battery power supply, and a location transponder working on the international standard 37.5 kHz. The bell may also have viewports and a medical lock.

A closed bell may be fitted with an umbilical cutter, a mechanism which allows the occupants to sever the bell umbilical from inside the sealed and pressurised bell in the event of an umbilical snag that prevents bell recovery. The device is typically hydraulically operated using a hand pump inside the bell, and can shear the umbilical at or just above the point where it is fastened to the top of the bell. Once cut, the bell can be raised and if the umbilical can then be recovered, it can be reconnected with only a short length lost. An external connection known as a hot stab unit which allows an emergency umbilical to be connected to maintain life support in the bell during a rescue operation may be fitted.

The divers in the bell may also be monitored from the diving control point by closed circuit video, and the bell atmosphere can be monitored for volatile hydrocarbon contamination by a hyperbaric hydrocarbon analyser which can be linked to a topside repeater and set to give an alarm if the hydrocarbon levels exceed 10% of the anaesthetic level.

The bell may be fitted with an external emergency battery power pack, carbon dioxide scrubber for the internal atmosphere, and air conditioner for temperature control. Power supply is typically 12 or 24V DC.

A bell will be provided with equipment to rescue and treat an injured diver. This will normally include a small tackle to lift the disabled diver into the bell through the bottom hatch and secure them in an upright position if needed. A bell flooding valve, also known as a flood-up valve may be available to partially flood the interior to aid in lifting a disabled diver into the bell. Once inside and secure, the bell is cleared of water using the blow-down valve to fill the interior with breathing gas at ambient pressure and displace the water out through the hatch. A first aid kit will be carried.

British mini-bell system
A variant of this system used in the North Sea oilfields between early 1986 and the early 90s was the Oceantech Minibell system, which was used for bell-bounce dives, and was operated as an open bell for the descent, and as a closed bell for the ascent. The divers would climb into the bell after stowing their umbilicals on outside racks, remove their helmets for outside storage, seal the bell, and return to the surface, venting to the depth of the first decompression stop. The bell would then be locked onto a deck decompression chamber, the divers transferred under pressure to complete decompression in the chamber, and the bell would be available for use for another dive.

Breathing gas distribution
Breathing gas supplies for the bell comprise a primary gas supply, a reserve gas supply and an emergency gas supply carried on the bell. The divers will also carry bailout gas in scuba cylinders, or as a semi-closed circuit rebreather, sufficient to get them back to the bellin the event of an umbilcal supply failure.

Primary gas, or main gas supply may be compressed air, which is usually supplied by a low pressure breathing air compressor, or mixed gas, which is usually provided in manifolded clusters of high-pressure storage cylinders, commonly referred to as "quads". Primary gas is connected to the main gas panel throughout the diving operation except when it fails or a problem is being corrected, during which time the divers are switched over to reserve gas.

Reserve gas, or secondary gas, which is connected to the main gas panel and available for immediate use by opening the supply valve, may also be supplied by low pressure compressor, or from high pressure storage. It has the same composition as the main gas supply.

Decompression gas, when used, is also supplied via the main gas panel. It may be the same gas as the primary gas, or an oxygen enriched mixture, or pure oxygen. Gas switching for in-water decompression in a wet bell is not the preferred procedure for commercial diving, as the entire breathing gas delivery system must be oxygen clean, and as a decompression chamber is required on site when a specified limit of obligatory decompression is planned, it is more convenient to do surface decompression on oxygen (SurDO2)in the chamber. The relative safety of surface decompression and in-water decompression is uncertain. Both procedures are accepted by health and safety regulatory bodies.

Emergency gas is carried on the bell, usually in a small number of 50 litre high-pressure cylinders connected to the bell gas panel. This should be the same gas as the primary gas. On closed bells there is an additional supply of pure oxygen if the bell has a carbon dioxide scrubber for the bell atmosphere. On a type 2 wet bell or a closed bell this emergency gas can be distributed to the divers from the bell gas panel operated by the bellman, through the excursion umbilicals,.

Each diver carries an emergency gas supply (bailout gas) sufficient to get back to the bell under any reasonably foreseeable circumstances of umbilical supply failure of primary, reserve, and bell emergency gas supplies.

The main gas distribution panel is located at the control point for the diving operation, and operated by the gas man, who may also be a diver, or if the gas is air, it may be directly operated by the diving supervisor.

Bell gas panel
The bell gas panel is a manifold of valves, pipes, hoses and gauges mounted inside a closed bell, and under the canopy of a type 2 wet bell, and is operated by the bellman. When a helium reclaim system is in use, the return hose for the reclaimed gas passes through the bell gas panel and a back-pressure regulator on its way to the surface.The bell gas panel is supplied with primary and secondary gas supplies from the main gas panel through the bell umbilical, and with on-board emergency gas from the cylinders carried on the bell.

Deployment of a modern diving bell
Diving bells are deployed over the side of the vessel or platform, or through a moonpool, using a gantry or A-frame from which the clump weight and the bell are suspended. On dive support vessels with in-built saturation systems the bell may be deployed through a moon pool. The bell handling system is also known as the launch and recovery system (LARS).

The bell umbilical supplies gas to the bell gas panel, and is separate from the divers' excursion umbilicals, which are connected to the gas panel on the inside of the bell. The bell umbilical is deployed from a large drum or umbilical basket and care is taken to keep the tension in the umbilical low but sufficient to remain near vertical in use and to roll up neatly during recovery, as this reduces the risk of the umbilical snagging on underwater obstructions.

Wet bell handling differs from closed bell handling in that there is no requirement to transfer the bell to and from the chamber system to make a pressure-tight connection, and that a wet bell will be required to maintain a finely controlled speed of descent and ascent and remain at a fixed depth within fairly close tolerances for the occupants to decompress at a specific ambient pressure, whereas a closed bell can be removed from the water without delay and the speed of ascent and descent is not critical.

A bell diving team will usually include two divers in the bell, designated as the working diver and bellman, though they may alternate these roles during the dive. The bellman is a stand-by diver and umbilical tender from the bell to the working diver, the operator of the on-board gas distribution panel, and has an umbilical about 2 m longer than the working diver to ensure that the working diver can be reached in an emergency. This can be adjusted by tying off the umbilicals inside the bell to limit deployment length, which must often be done in any case, to prevent the divers from approaching known hazards in the water. Depending on circumstances, there may also be a surface stand-by diver, with attendant, in case there is an emergency where a surface oriented diver could assist. The team will be under the direct control of the diving supervisor, will include a winch operator, and may include a dedicated surface gas panel operator.

Clump weight
Deployment of a diving bell usually starts by lowering the clump weight, which is a large ballast weight suspended in the bight of a cable which runs from a winch, over a sheave on one side of the gantry, down to the weight, round a pair of sheaves on the sides of the weight, and back up to the other side of the gantry, where it is fastened. The weight hangs freely between the two parts of the cable, and due to its weight, hangs horizontally and keeps the cable under tension. The bell hangs between the parts of the clump weight cable, and has a fairlead on each side which slides along the cable as it is lowered or lifted. Deployment of the bell is by a separate cable attached to the top, which runs over a sheave in the middle of the gantry. As the bell is lowered, the fairleads prevent it from rotating on the deployment cable, which would put twist into the umbilical and risk loops or snagging. The clump weight cables therefore act as guidelines or rails along which the bell is lowered to the workplace, and raised back to the platform. If the lifting winch or cable fails, and the bell ballast is released, a positively buoyant bell can float up and the cables will guide it to the surface to a position where it can be recovered relatively easily. The clump weight cable can also be used as an emergency recovery system, in which case both bell and weight are lifted together. An alternative system for preventing rotation on the lifting cable is the use of a cross-haul system, which may also be used as a means of adjusting the lateral position of the bell at working depth, and as an emergency recovery system.

Bell stage
A bell stage is an open framework below the bell which prevents the bell lower lock from getting too close to the clump weight or seabed, ensuring that there is space for the divers to safely exit and enter the bell. This can be deployed either as part of the bell, or as part of the clump weight. The bell stage may be fitted with baskets for carrying tools and equipment.

Bell handling system
A closed bell handling system is used to move the bell from the position where it is locked on to the chamber system into the water, lower it to the working depth and hold it in position without excessive movement, and recover it to the chamber system. The system used to transfer the bell on deck may be a deck trolley system, an overhead gantry or a swinging A-frame. The system must constrain movement of the supported bell sufficiently to allow accurate location on the chamber trunking even in bad weather. A bell cursor may be used to control movement through and above the splash zone, and heave compensation gear may be used to limit vertical movement when in the water and clear of the cursor, particularly at working depth when the diver may be locked out and the bell is open to ambient pressure.

Bell cursor
A bell cursor is a device used to guide and control the motion of the bell through the air and the splash zone near the surface, where waves can move the bell significantly. It can either be a passive system which relies on additional ballast weight or an active system which uses a controlled drive system to provide vertical motion. The cursor has a cradle which locks onto the bell and which moves vertically on rails to constrain lateral movement. The bell is released and locked onto the cursor in the relatively still water below the splash zone.

Heave compensation
Heave compensation equipment is used to stabilise the depth of the bell by counteracting vertical movement of the handling system caused by movements of the platform, and usually also maintains correct tension on the guide wires. It is not usually essential, depending on the stability of the platform.

Cross-hauling
Cross-hauling systems are cables from an independent lifting device which are intended to be used to move the bell laterally from a point directly below the LARS, and may also be used to limit rotation and as an emergency bell recovery system.

Use with hyperbaric chambers
Commercial diving contractors generally use a closed bell in conjunction with a surface hyperbaric chamber, These have safety and ergonomic advantages and allow decompression to be carried out after the bell has been raised to the surface and back on board the diving support vessel. Closed bells are often used in saturation diving and undersea rescue operations. The diving bell would be connected via the mating flange of an airlock to the deck decompression chamber or saturation system for transfer under pressure of the occupants. Use of hyperbaric chambers underwater can be dangerous, hyperbaric chambers are prone to lighting on fire from the inside.

Air-lock diving bells
The air lock diving-bell plant was a purpose-built barge for the laying, examination and repair of moorings for battleships at Gibraltar harbour. It was designed by Siebe Gorman of Lambeth and Forrestt & Co. Ltd of Wivenhoe in Essex, who built and supplied it in 1902 to the British Admiralty.

The vessel came about from the specific conditions at Gibraltar. The heavy harbour moorings have three chains extending out radially along the seabed from a central ring, each terminating in a large anchor. Most harbours have a soft seabed, and it is usual to lay down moorings by settling anchors in the mud, clay or sand but this could not be done in Gibraltar harbour, where the seabed is hard rock.

In operation the barge would be towed over the work site, moored in place with anchors, and the bell would be lowered vertically to the bottom. and the water displaced by pumping. The work teams entered the bell through an airlock in the central access shaft. Working in ordinary clothes they could dig out anchorings for the moorings.

The German service barge Carl Straat is similar in concept, but the bell is lowered by swinging the access tube. Carl Straat was built in 1963 for the Waterways and Shipping Directorate West in Münster. The 6 m × 4 m × 2.5 m bell is accessible through a 2 m diameter tube and an airlock. A pantograph system keeps the bell and internal stairs level at all depths. Maximum working depth is 10 m. The vessel is used on those inland waterways which have locks large enough to accommodate its 52 m length overall, 11.8 m beam and 1.6 m draft.

Rescue bell
Diving bells have been used for submarine rescue. The closed, dry bell is designed to seal against the deck of the submarine above an escape hatch. Water in the space between the bell and the submarine is pumped out, and the pressure difference holds the bell against the submarine, so the hatches can be opened to allow occupants to leave the submarine and enter the bell. The hatches are then closed, the bell skirt flooded to release it from the submarine, and the bell with its load of survivors is hoisted back to the surface, where the survivors exit and the bell may return for the next group. The internal pressure in the bell is usually kept at atmospheric pressure to minimise run time by eliminating the need for decompression, so the seal between the bell skirt and the submarine deck is critical to the safety of the operation. This seal is provided by using a flexible sealing material, usually a type of rubber, which is pressed firmly against the smooth hatch surround by the pressure differential when the skirt is pumped out.

Observation bell
An observation bell is a closed bell, generally operated with internal pressure at atmospheric pressure, which provides an observation platform that can be lowered to depth with one or more occupants who can observe the environment through viewports, but are generally not provided with a means of interacting physically with the outside environment. The first observation bell was one of the first modern bells constructed in the late 19th century.

The bathysphere and observation bell are similar structures. A steel bathysphere created in 1930 by William Beebe and Otis Barton had three crystal glass windows made for observation. Observation bells for shallower depths generally use different designs to bathyspheres.

Bell diving skills and procedures
Routine procedures for bell diving include preparation of the bell for the dive, descent and ascent, and monitoring of the working diver by the bellman. The bellman is responsible for ensuring that the bell and its occupants are ready for descent or ascent, and for communications with the surface for tenting the working diver's umbilical and for operation of the bell gas panel.

A wet bell ascent usually includes decompression stops in the water, and sometimes surface decompression.

Closed bell procedures also include locking in and locking out at depth, and transfer under pressure between bell and the saturation system or a deck decompression chamber.

Emergency bell procedures include dynamic positioning alarm and runout response, emergency bell gas panel operations, such as surface gas supply failure or contaminated surface gas supply, both of which require bailout to onboard gas, hot water supply failure, and rescue of the working diver by the bellman. Voice communications failure requires appropriate use of emergency light and gas signals. Bell abandonment may be necessary if a wet bell cannot be raised, but saturation divers in a closed bell must be rescued in the bell or to another bell as they cannot be surfaced in-water.

Hazards
A closed bell that has been depressurised for maintenance access will probably retain residual diving breathing gas mixture, which will usually be hypoxic at normal atmospheric pressure, and could cause anyone who enters to lose consciousness quite rapidly. Helium based mixtures are buoyant and require active flushing with a strong flow of air, followed by testing for oxygen partial pressure before entry.

The bell atmosphere can be contaminated by materials brought in by a diver who was exposed to the contaminants during the lock-out. These will depend on the working environment, and may include petrochemicals. This is a greater problem with closed bells.

Diver training
Divers qualified to work from bells are trained in the skills and procedures relevant to the type of bell they will be expected to work from. Open bells are generally used for surface oriented surface-supplied deep air diving, and closed bells are used for saturation diving and surface oriented mixed gas diving. These skills include the standard procedures for the deployment of the working diver from the bell, the tending of the working diver from the bell by the bellman, and the emergency and rescue procedures for both working diver and bellman. There is considerable similarity and significant differences in these procedures between open and closed bell diving.

Underwater habitats
As noted above, further extension of the wet bell concept is the moon-pool-equipped underwater habitat, where divers may spend long periods in dry comfort while acclimated to the increased pressure experienced underwater. By not needing to return to the surface between excursions into the water, they can reduce the necessity for decompression (gradual reduction of pressure), after each excursion, required to avoid problems with nitrogen bubbles releasing from the bloodstream (the bends, also known as caisson disease). Such problems can occur at pressures greater than 1.6 atm, corresponding to a depth of 6 m of water. Divers in an ambient pressure habitat will require decompression when they return to the surface. This is a form of saturation diving.

In nature
The diving bell spider, Argyroneta aquatica, is a spider which lives entirely under water, even though it could survive on land.

Since the spider must breathe air, it constructs from silk a habitat like an open diving bell which it attaches to an underwater plant. The spider collects air in a thin layer around its body, trapped by dense hairs on its abdomen and legs. It transports this air to its diving bell to replenish the air supply in the bell. This allows the spider to remain in the bell for long periods, where it waits for its prey.

title: Diving bell


text:
Symmetric algebra

In mathematics, the symmetric algebra $S(V)$ (also denoted $Sym(V))$ on a vector space $V$ over a field $K$ is a commutative algebra over $K$ that contains $V$, and is, in some sense, minimal for this property. Here, "minimal" means that $S(V)$ satisfies the following universal property: for every linear map $f$ from $V$ to a commutative algebra $A$, there is a unique algebra homomorphism $g : S(V) → A$ such that $f = g ∘ i$, where $i$ is the inclusion map of $V$ in $S(V)$.

If $B$ is a basis of $V$, the symmetric algebra $S(V)$ can be identified, through a canonical isomorphism, to the polynomial ring $K[B]$, where the elements of $B$ are considered as indeterminates. Therefore, the symmetric algebra over $V$ can be viewed as a "coordinate free" polynomial ring over $V$.

The symmetric algebra $S(V)$ can be built as the quotient of the tensor algebra $T(V)$ by the two-sided ideal generated by the elements of the form $x ⊗ y − y ⊗ x$.

All these definitions and properties extend naturally to the case where $V$ is a module (not necessarily a free one) over a commutative ring.

From tensor algebra
It is possible to use the tensor algebra $T(V)$ to describe the symmetric algebra $S(V)$. In fact, $S(V)$ can be defined as the quotient algebra of $T(V)$ by the two-sided ideal generated by the commutators $$v\otimes w - w\otimes v.$$

It is straightforward to verify that the resulting algebra satisfies the universal property stated in the introduction. Because of the universal property of the tensor algebra, a linear map $f$ from $V$ to a commutative algebra $A$ extends to an algebra homomorphism $$T(V)\rightarrow A$$, which factors through $S(V)$ because $A$ is commutative. The extension of $f$ to an algebra homomorphism $$S(V)\rightarrow A$$ is unique because $V$ generates $S(V)$ as a $K$-algebra.

This results also directly from a general result of category theory, which asserts that the composition of two left adjoint functors is also a left adjoint functor. Here, the forgetful functor from commutative algebras to vector spaces or modules (forgetting the multiplication) is the composition of the forgetful functors from commutative algebras to associative algebras (forgetting commutativity), and from associative algebras to vectors or modules (forgetting the multiplication). As the tensor algebra and the quotient by commutators are left adjoint to these forgetful functors, their composition is left adjoint to the forgetful functor from commutative algebra to vectors or modules, and this proves the desired universal property.

From polynomial ring
The symmetric algebra $S(V)$ can also be built from polynomial rings.

If $V$ is a $K$-vector space or a free $K$-module, with a basis $B$, let $K[B]$ be the polynomial ring that has the elements of $B$ as indeterminates. The homogeneous polynomials of degree one form a vector space or a free module that can be identified with $V$. It is straightforward to verify that this makes $K[B]$ a solution to the universal problem stated in the introduction. This implies that $K[B]$ and $S(V)$ are canonically isomorphic, and can therefore be identified. This results also immediately from general considerations of category theory, since free modules and polynomial rings are free objects of their respective categories.

If $V$ is a module that is not free, it can be written $$V=L/M,$$ where $L$ is a free module, and $M$ is a submodule of $L$. In this case, one has
 * $$S(V)=S(L/M)=S(L)/\langle M\rangle,$$

where $$\langle M\rangle$$ is the ideal generated by $M$. (Here, equals signs mean equality up to a canonical isomorphism.) Again this can be proved by showing that one has a solution of the universal property, and this can be done either by a straightforward but boring computation, or by using category theory, and more specifically, the fact that a quotient is the solution of the universal problem for morphisms that map to zero a given subset. (Depending on the case, the kernel is a normal subgroup, a submodule or an ideal, and the usual definition of quotients can be viewed as a proof of the existence of a solution of the universal problem.)

Grading
The symmetric algebra is a graded algebra. That is, it is a direct sum
 * $$S(V)=\bigoplus_{n=0}^\infty S^n(V),$$

where $$S^n(V),$$ called the $n$th symmetric power of $V$, is the vector subspace or submodule generated by the products of $n$ elements of $V$. (The second symmetric power $$S^2(V)$$ is sometimes called the symmetric square of $V$).

This can be proved by various means. One follows from the tensor-algebra construction: since the tensor algebra is graded, and the symmetric algebra is its quotient by a homogeneous ideal: the ideal generated by all $$x \otimes y - y \otimes x,$$ where $x$ and $y$ are in $V$, that is, homogeneous of degree one.

In the case of a vector space or a free module, the gradation is the gradation of the polynomials by the total degree. A non-free module can be written as $L / M$, where $L$ is a free module of base $B$; its symmetric algebra is the quotient of the (graded) symmetric algebra of $L$ (a polynomial ring) by the homogeneous ideal generated by the elements of $M$, which are homogeneous of degree one.

One can also define $$S^n(V)$$ as the solution of the universal problem for $n$-linear symmetric functions from $V$ into a vector space or a module, and then verify that the direct sum of all $$S^n(V)$$ satisfies the universal problem for the symmetric algebra.

Relationship with symmetric tensors
As the symmetric algebra of a vector space is a quotient of the tensor algebra, an element of the symmetric algebra is not a tensor, and, in particular, is not a symmetric tensor. However, symmetric tensors are strongly related to the symmetric algebra.

A symmetric tensor of degree $n$ is an element of $Tn(V)$ that is invariant under the action of the symmetric group $$\mathcal S_n.$$ More precisely, given $$\sigma\in \mathcal S_n,$$ the transformation $$v_1\otimes \cdots \otimes v_n \mapsto v_{\sigma(1)}\otimes \cdots \otimes v_{\sigma(n)}$$ defines a linear endomorphism of $Tn(V)$. A symmetric tensor is a tensor that is invariant under all these endomorphisms. The symmetric tensors of degree $n$ form a vector subspace (or module) $Symn(V) ⊂ Tn(V)$. The symmetric tensors are the elements of the direct sum $$\textstyle \bigoplus_{n=0}^\infty \operatorname{Sym}^n(V),$$ which is a graded vector space (or a graded module). It is not an algebra, as the tensor product of two symmetric tensors is not symmetric in general.

Let $$\pi_n$$ be the restriction to $Symn(V)$ of the canonical surjection $$T^n(V)\to S^n(V).$$ If $n!$ is invertible in the ground field (or ring), then $$\pi_n$$ is an isomorphism. This is always the case with a ground field of characteristic zero. The inverse isomorphism is the linear map defined (on products of $n$ vectors) by the symmetrization
 * $$v_1\cdots v_n \mapsto \frac 1{n!} \sum_{\sigma \in S_n} v_{\sigma(1)}\otimes \cdots \otimes v_{\sigma(n)}.$$

The map $$\pi_n$$ is not injective if the characteristic is less than $n$+1; for example $$\pi_n(x\otimes y+y\otimes x) = 2xy$$ is zero in characteristic two. Over a ring of characteristic zero, $$\pi_n$$ can be non surjective; for example, over the integers, if $x$ and $y$ are two linearly independent elements of $V = S1(V)$ that are not in $2V$, then $$xy\not\in \pi_n(\operatorname{Sym}^2(V)),$$ since $$\frac 12 (x\otimes y +y\otimes x) \not\in \operatorname{Sym}^2(V).$$

In summary, over a field of characteristic zero, the symmetric tensors and the symmetric algebra form two isomorphic graded vector spaces. They can thus be identified as far as only the vector space structure is concerned, but they cannot be identified as soon as products are involved. Moreover, this isomorphism does not extend to the cases of fields of positive characteristic and rings that do not contain the rational numbers.

Categorical properties
Given a module $V$ over a commutative ring $K$, the symmetric algebra $S(V)$ can be defined by the following universal property:

 * For every $K$-linear map $f$ from $V$ to a commutative $K$-algebra $A$, there is a unique $K$-algebra homomorphism $$g:S(V)\to A$$ such that $$f=g\circ i,$$ where $i$ is the inclusion of $V$ in $S(V)$.

As for every universal property, as soon as a solution exists, this defines uniquely the symmetric algebra, up to a canonical isomorphism. It follows that all properties of the symmetric algebra can be deduced from the universal property. This section is devoted to the main properties that belong to category theory.

The symmetric algebra is a functor from the category of $K$-modules to the category of $K$-commutative algebra, since the universal property implies that every module homomorphism $$f:V\to W$$ can be uniquely extended to an algebra homomorphism $$S(f):S(V)\to S(W).$$

The universal property can be reformulated by saying that the symmetric algebra is a left adjoint to the forgetful functor that sends a commutative algebra to its underlying module.

Symmetric algebra of an affine space
One can analogously construct the symmetric algebra on an affine space. The key difference is that the symmetric algebra of an affine space is not a graded algebra, but a filtered algebra: one can determine the degree of a polynomial on an affine space, but not its homogeneous parts.

For instance, given a linear polynomial on a vector space, one can determine its constant part by evaluating at 0. On an affine space, there is no distinguished point, so one cannot do this (choosing a point turns an affine space into a vector space).

Analogy with exterior algebra
The Sk are functors comparable to the exterior powers; here, though, the dimension grows with k; it is given by
 * $$\operatorname{dim}(S^k(V)) = \binom{n+k-1}{k}$$

where n is the dimension of V. This binomial coefficient is the number of n-variable monomials of degree k. In fact, the symmetric algebra and the exterior algebra appear as the isotypical components of the trivial and sign representation of the action of $$S_n$$ acting on the tensor product $$V^{\otimes n}$$ (for example over the complex field)

As a Hopf algebra
The symmetric algebra can be given the structure of a Hopf algebra. See Tensor algebra for details.

As a universal enveloping algebra
The symmetric algebra S(V) is the universal enveloping algebra of an abelian Lie algebra, i.e. one in which the Lie bracket is identically 0.

title: Symmetric algebra


text:
Operation Deckhouse Five

Operation Deckhouse Five was a United States Marine Corps (USMC) and Republic of Vietnam Marine Corps operation that took place from 6–15 January 1967 in the Mekong Delta, during the Vietnam War. "The ten-day sweep," reported the AP from its daily military roundup from Saigon, "proved unproductive."

Background
For the USMC, the operation was notable for the following reasons: it was a sizable, combined USMC and Vietnamese Marine amphibious operation and it was the last Special Landing Force (SLF) amphibious landing to take place beyond the boundaries of I Corps. An SLF was the designation of the Marine battalion (1st Battalion, 9th Marine Regiment reinforced) and the medium helicopter squadron (HMM) assigned to the Seventh Fleet Amphibious Ready Group. The SLF regularly conducted amphibious operations across Vietnamese beaches into areas of suspected Viet Cong and People's Army of Vietnam (PAVN) activity. The intent of the operation was to secure ammunition dumps, ordnance and engineering workshops, hospitals, and indoctrination centers.

Operation
After 2 days of postponement due to bad weather, the operation began on 6 January with a sea and heliborne assault onto the beaches between the Co Chien and Ham Luong branches of the Mekong Delta which was suspected of being a Viet Cong stronghold.

Supporting units

 * HMM-362
 * VMO-3
 * USS Iwo Jima (LPH-2)
 * USS Canberra (CA-70)

Aftermath
The operation was a ‘disappointment’ resulting in ‘only’ 21 Vietcong killed, 2 small arms workshops destroyed and 44 weapons captured for the loss of 7 US and 1 Vietnamese Marines. It was believed that the Vietcong had been forewarned of the attack because intelligence learned that larger Vietcong units had recently left the area.

title: Operation Deckhouse Five


text:
Tom Leonard

Tom or Thomas Leonard may refer to:

 * Tom Leonard (Irish politician) (1924–2004), Fianna Fáil politician from Dublin, Ireland
 * Tom Leonard (poet) (1944–2018), Scottish poet
 * Thomas J. Leonard (1955–2003), founder of Coach University
 * Tom Leonard (tennis) (born 1948), American former tennis player
 * Thomas D'Arcy Leonard (1895–1977), Canadian politician and corporate executive
 * Thomas Arthur Leonard (1864–1948), British social reformer
 * Thomas H. Leonard (born 1948), British statistician and author
 * Tom Leonard (Michigan politician) (born 1981), member of the Michigan House of Representatives
 * Thomas C. Leonard, economics academic
 * Thomas Léonard (born 1981), French football referee

title: Tom Leonard