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Talk:Poincaré conjecture/Archive 1

A call to arms
It seems likely (given the strengths of the verified breakthroughs) that Perelman's proof of PC w ill be found correct, and it behooves the Wikipedia community to get working on cleaning up this page.

IMHO, there is a good chance that within the year, major figures in the mathematical community will announce their confidence in Perelman's proof of PC. When this happens, there will be major media attention, like when the news about Perelman first broke. Recall that when the media first got interested, several journalists actually referenced and quoted the Wikipedia article on PC.

I think everyone should put more effort into this page and work to make it at the level of a featured article. If we can get a lot of people looking at this page, journalists included, then this can only further Wikipedia's cause.

Recent progress in solving the problem
Grigori Perelman may have solved another problem called Thurston's conjecture.

Poincaré's conjecture is a special case of Thurston's conjecture, so a proof of Thurston's conjecture immediately proves the Poincaré Conjecture.

Consequently Perelman may be in line for the Clay Millennium Problem million dollar prize.

 * Re the proof, Tosha would probably know if there were a problem. Charles Matthews 11:18, 18 May 2004 (UTC)

Also, There is as-yet no problem with the proof, and it is widely accepted; maybe the page should change to reflect this? Gartogg, Sep. 2, 04

 * No problem with the proof so far does not imply "widely accepted"! No respected mathematician has come forth saying s/he finds it correct.  Currently, Kleiner, Lott, et al, are not confident of all the details and assertions of the second Perelman paper.

-

I was wondering what the word "closed" in the conjecture means. Is it "compact and wouthout boundary"? If so, we should probably clarify, since "closed" is used in other meanings as well. AxelBoldt

 * Yes, it means "compact and without boundary". This is explained in the manifold article, but it might well be best to clarify it anyway. --Zundark, 2002 Feb 19

Could someone merge the information from Poincaré Conjecture (note capital C) into this article and then make the other one redirect here? -- Timwi 00:14 29 Jun 2003 (UTC)

I don't think there's any useful extra information there, but I've moved the contents here (below), just in case anyone disagrees. --Zundark 13:27 2 Jul 2003 (UTC)

The Poincaré Conjecture is a topological problem. It is one of the most well known problems in mathematics, after Fermat's Last Theorem. The problem was formulated by Henri Poincaré in 1904.

Here is the problem, taken from the official problem description (an Adobe Acrobat PDF)

 * Consider a compact 3-dimensional manifold V without a boundary.

 * Is it possible that the fundamental group of V could be trivial, even though V is not homeomorphic to the 3-dimensional sphere?

The problem is the subject of a one million dollar prize at the Clay Mathematics Institute.

Popular descriptions of this conjecture are surprisingly dependent upon international culinary definitions. Most descriptions of the conjecture involve comparing the result of constricting a spherical object with the effects of performing a similar constriction exercise upon a doughnut-shaped object.

Unfortunately, there are two types of doughnut, one of which is a torus or ring (a 'ring doughnut') and the other variety is approximately spherical (called a 'jam doughnut' in the UK because it is typically filled with what the British call jam, and called a jelly doughnut in the USA because they call the same filling jelly) and this doughnut dichotomy has the potential to render the standard explanation of the Poincaré conjecture unintelligibly confusing.

The (admittedly mischevious, not to mention potentially frivolous) suspicion is that the two different types of doughnut divide Europe from the United States and this may be in part responsible for the longevity of the unsolved mystery of the problem.

Edit of User:C S
I do not like this edit. The article should be reasonably short, such things a sphere, homomorphism and so on one can learn elsewhere. Tosha 05:48, 6 Sep 2004 (UTC)

 * Length is a problem, as always; I agree that there shouldn't be too much explanation.

 * The current version is unsatisfactory since it does not explain the history or motivation. The content basically consists of comments about the higher dimensional conjectures, a short comment about the statement of the conjecture, and several paragraphs about Perelman and his work.  This does not do justice to such a venerable conjecture as the Poincare Conjecture.

 * I wonder how carefully you read the edit. I do not attempt to explain "homeomorphism", at least not explicitly.  There is other material besides that on spheres.  I think my edit gives the entry room to grow, unlike the current revision, and so your (basically) complete revert is a step backwards.  So what I will do is keep some of the stuff about motivation, e.g. homology spheres, and some history, but cut out the the long explanation.  I think we should move to having some more explanation though.

--C S 07:40, Sep 6, 2004 (UTC)

 * Keep in mind it is not natural to treat this conjecture identically as one would any other. PC is special, being tractable, as a statement, to non-mathematicians, and yet profoundly difficult to mathematicians. It's an intriguing combination. In my arrogant opinion, it is incumbant on the wiki (and mathematics) community to bolster that intrigue, i.e., broad accessibility is good here. MotherFunctor

Poincare's invention of the fundamental group
Regarding:

 * He then applied another tool, called the fundamental group. He wondered if a 3-manifold with trivial fundamental group had to be a 3-sphere.

which was changed from the statement, "He then came up with..."

The point I was trying to make was that his invention of the fundamental group was motivated by desire to get a finer invariant of the 3-sphere than the homology groups (in particular the first homology group). The revised statement gives the impression he just had another tool handy, instead of emphasizing that in this case, as usual, "necessity was the mother of invention".

There's a lot of mathematics invented by Poincare just to form the conjecture, and then of course, even more was invented to try and prove it. We should try to emphasize this to give the conjecture its due. --C S 15:19, Sep 8, 2004 (UTC)

 * It seems he introduced the fundamental group in 1894, though. Charles Matthews 16:13, 8 Sep 2004 (UTC)

 * Milnor gives the approximate date as 1900-1904 in the external links articles by him. But I just noticed that in the published versioin of "Towards the Poincare Conjecture..." he changes it to 1895!  I'm guessing the editor caught the mistake.  Thanks.

--C S 00:20, Sep 9, 2004 (UTC)

I do not know history of the question at all, is it true that fundumental group was envented only after homology groups? Tosha

 * Let me clarify my response to Charles Matthews and answer your question. Milnor's article gives the date of publication for the concept of fundamental group as 1895, and I corroborated this by checking the date of the document in question, which I found, for example, by checking the University of St. Andrews biographies website.

 * However, I decided to dig through some history books, mainly Klein's 3-volume history. The papers he wrote after 1895, which includes the one (1904) in which he asked if fundamental group distinguishes the 3-sphere, were supplements to the 1895 paper.  In the 1895 paper he not only defines the fundamental group, but talks about the Betti numbers and proves, in fact, Poincare Duality.  So at this point, it looks like the fundamental group was invented more or less during the time Poincare was thinking about homology.

 * One thing to note though, is that Poincare thought of homology as Betti numbers and torsion coefficients. I think the idea of thinking of homology groups came along later.

 * In terms of what to fix in the article, we should mention that Poincare's work on homology was based on earlier work by Enrico Betti. Also, it should be mentioned that Poincare was able to distinguish the Poincare sphere from the 3-sphere using the fundamental group (1904).  Earlier, in 1900 he had claimed that homology (i.e. Betti numbers and torsion coefficients) would distinguish the 3-sphere.  So he was led naturally to add the simple-connectivity condition.  I'll straighten this out in the article.--C S 05:47, Sep 9, 2004 (UTC)

I think the history needs to be added with a little care. Please note that there are historical remarks already in the Poincaré duality article. I feel it is clear that PD was more significant an influence on others than PC, up to 1930 (say). I am also fairly clear that the definition of the fundamental group was available during the 1890s, just because so much had been done on monodromy. There are also historical remarks to make about Stokes' theorem (1899) and de Rham cohomology, and torsion and the formulation of homology as abelian groups (Emmy Noether); and other matters such as Poincaré polynomials and the Kunneth theorem. I really think this is diffucult all to hang on the Poincaré conjecture peg.

A timeline of homology theory might therefore be better.

Charles Matthews 08:52, 9 Sep 2004 (UTC)

 * I agree that things shouldn't get too overloaded with historical detail. But I wanted to motivate why Poincare would settle upon simple-connectivity as the fundamental condition.  I think that's been done, more or less, without making the section on the statement unwieldy; do you agree?  With my last change, I just wanted to straighten out the historical order.  I'm not planning on adding more to that section.

 * If you're worried I'm going to transfer all the stuff from the talk page I've written to the article, don't worry. I was just overexplaining things.  I agree that stuff like Poincare Duality and facts about homology should have their own pages, but in the case of homology spheres, I felt it should be mentioned.

 * Perhaps I shouldn't have added the part on Betti, but I wanted to credit Poincare in the article without being unfair.--C S 09:14, Sep 9, 2004 (UTC)

The current section on the statement seems to be more or less OK. Charles Matthews 09:29, 9 Sep 2004 (UTC)

Applications
I would remove this subsection, it is bit misleading and does not add much to the article. Tosha

Yes, it would be better on the Thurston conjecture page. Charles Matthews 18:59, 9 Sep 2004 (UTC)

I'm not sure any part of it fits on the Thurston conjecture page. But anyway, I moved the section here, in case anyone wants to salvage some part of it. --C S 01:38, Sep 10, 2004 (UTC)

The three-dimensional Poincaré Conjecture is related to the problem of classifying 3-manifolds. A "classification of 3-manifolds" is generally accepted to mean that one can generate a list of all 3-manifolds up to homeomorphism with no repetitions. Such a classification is equivalent to a recognition algorithm, which would be able to check if two 3-manifolds were homeomorphic or not.

Thurston's geometrization conjecture, in addition to containing the Poincare Conjecture as a special case, is known to imply a classification of 3-manifolds.

It is not true that any two 3-manifolds can be distinguished by their fundamental groups. In fact, J.W. Alexander showed in 1919 that there are lens spaces with isomorphic fundamental groups but are not homeomorphic. On the other hand, these kinds of examples are seen as exceptions, and it is generally believed that most 3-manifolds are determined by their fundamental groups. The Poincaré Conjecture is therefore an important test case of this heuristic.

Homotopy spheres
The statement given in terms of homotopy spheres could be a lot clearer. The product of a sphere with the real line is a counterexample to what is currently said. Charles Matthews 14:58, 13 Apr 2005 (UTC)

 * Fixed. The dimension should be specified and now is. --C S 07:15, Jun 24, 2005 (UTC)

what does the final step mean?
see the lastest link in the introduction page.

Is it obvious from Thurston's geometrization conjecture to Poincaré conjecture or there really still need a 300-pages proof? just want know the importance of the china scientist work. —Preceding unsigned comment added by mathematic (talk • contribs)

 * The paper isn't about going from geometrization to Poincare: that, as you suspect, is trivial and requires at most a short paragraph (see elliptization conjecture for short explanation). I haven't looked at the article, but I read the abstract.  It sounds like they have basically a complete write up of Perelman's work, with probably details that he didn't fully explain, and probably cast and reformulated somewhat differently.  The Xinhua article is very poorly written, and probably the headline and focus of the story gives a misleading impression of what the two mathematicians did.  --C S (Talk) 08:59, 4 June 2006 (UTC)

Interesting link
I found a very interesting link related to the Poincare's conjecture:. However I don't know if it is a hoax or not. Can someone verify their proof? --Matikkapoika 19:59, 4 June 2006 (UTC)

 * This is the same thing I responded to in the previous section. No hoax.  Just, well, a very interesting point of view that I think would not be universally agreed to.  It's an even worse article than the previous one mentioned...the quotes are kind of misleading, and I wonder if the journalist did a very selective job of quoting.  Both articles do not do a good job of explaining the different contributions (and kind of contributions).  One particularly bad thing is that this article's emphasis on Cao and Zhu's contributions comes at the expense of  lessening Perelman's contributions; however, it is clear that is is really Perelman's work that is significant, not theirs.  Of course, they have done something important here, which is to clarify Perelman's work...but other groups of people have and are doing this.  This team was apparently just one of the first to complete the task.  Perelman will probably win a Fields medal for what he did.  --C S (Talk) 22:19, 4 June 2006 (UTC)

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

title: Talk:Poincaré conjecture/Archive 1


text:
Talk:The Caves of Steel/Archive 1

ISBN: 0553293400  paper ISBN: 0785774459  hard cover ISBN: 0586008357 UK, paper

About this: Why link to linkbaton? Apparently they just forward to Amazon, and presumably make money in the Amazon affiliates program.

This is the preferred link:

[ISBN 0553293400] - paper [ISBN 0785774459] - hard cover [ISBN 0586008357] - UK, paper

 * See also : Isaac Asimov

No problem with the spoilers, but two issues with the article in general:

1. It doesn't make clear that the spacers are politically and militarily much stronger than Earth.

2. A lot of what is said in this article covers more than just the Caves of Steel. Maybe it's the fact that they are spoilers for other books that are connected with this one. There should probably be an article covering the series of novels as a whole.

Just my opinion.--BlackGriffen

title: Talk:The Caves of Steel/Archive 1


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Sigismund II Augustus

Sigismund II Augustus (Zygmunt II August, Žygimantas Augustas; 1 August 1520 – 7 July 1572) was King of Poland and Grand Duke of Lithuania, the son of Sigismund I the Old, whom Sigismund II succeeded in 1548. He was the first ruler of the Polish–Lithuanian Commonwealth and the last male monarch from the Jagiellonian dynasty.

Sigismund was the only son of Italian-born Bona Sforza and Sigismund the Old. From the beginning he was groomed and extensively educated as a successor. In 1529 he was crowned vivente rege while his father was still alive. Sigismund Augustus continued a tolerance policy towards minorities and maintained peaceful relations with neighbouring countries, with the exception of the Northern Seven Years' War which aimed to secure Baltic trade. Under his patronage, culture flourished in Poland; he was a collector of tapestries from the Low Countries and collected military memorabilia as well as swords, armours and jewellery. Sigismund Augustus' rule is widely considered as the apex of the Polish Golden Age; he established the first regular Polish navy and the first regular postal service in Poland, known today as Poczta Polska. In 1569 he oversaw the signing of the Union of Lublin between Poland and the Grand Duchy of Lithuania, which formed the Polish–Lithuanian Commonwealth and introduced an elective monarchy.

Sigismund Augustus married three times; his first wife, Elizabeth of Austria, died in 1545 at just eighteen. He was then involved in several relationships with mistresses, the most famous being Barbara Radziwiłł, who became Sigismund's second wife and Queen of Poland in spite of his mother's disapproval. The marriage was deemed scandalous and was fiercely opposed by the royal court and the nobility. Barbara died five months after her coronation, presumably due to ill health, however, rumours circulated that she was poisoned. Sigismund finally wedded Catherine of Austria, but remained childless throughout his life.

Sigismund Augustus was the last male member of the Jagiellonian dynasty. Following the death of his sister Anna in 1596 the Jagiellonian dynasty came to an end.

Early life
Sigismund Augustus was born in Kraków on 1 August 1520 to Sigismund I the Old and his wife, Bona Sforza of Milan. His paternal grandparents were Casimir IV Jagiellon, King of Poland, and Elizabeth of Austria. Sigismund's maternal grandparents, Gian Galeazzo Sforza and Isabella of Aragon, daughter of King Alfonso II of Naples, both ruled the Duchy of Milan until Sforza's suspicious death in 1494.

Throughout his youth, Sigismund Augustus was under the careful watch of his mother, Bona. Being the only legitimate male heir to the Polish throne throughout his father's reign, he was well educated and taught by the most renowned scholars in the country. It was also his mother's wish to name her only son Augustus, after the first Roman Emperor Augustus. However, this decision was met with Sigismund the Old's strong disapproval, who hoped for a lineage of Sigismunds on the Polish throne. Consequently, it was established that the child would bear two names to settle the conflict. The tradition of adopting Augustus as a second or middle name was also observed during the coronation of Stanisław Antoni Poniatowski who became King Stanisław II Augustus in 1764.

In 1529, Sigismund Augustus was inaugurated as Grand Duke of Lithuania and the ceremony was held in the Palace of the Grand Dukes of Lithuania in Vilnius.

In 1530, the ten-year-old Sigismund Augustus was crowned by Primate Jan Łaski as co-ruler alongside his father, in accordance with the vivente rege law. Sigismund the Old hoped to secure his son's succession to the throne and maintain the Jagiellonian dynasty's position in Poland. The move was crucial to silence the members of nobility who were against the Jagiellons and viewed the action as a step towards absolutism. The law was officially abolished by the Henrician Articles, or the new constitution adopted between the nobles and the newly elected King Henry of Valois in 1573.

Sigismund Augustus began his reign as the Grand Duke of the Grand Duchy of Lithuania in 1544 and initially opposed the Polish–Lithuanian union, thus hoping to leave his throne to his heirs.

First marriage
When Sigismund Augustus was co-crowned, Chancellor Krzysztof Szydłowiecki organized a preliminary marriage treaty between the young king and Elizabeth of Austria, daughter of King Ferdinand of Bohemia and Hungary. The marriage was signed on 10–11 November 1530 in Poznań, however, the arrangement was delayed by Queen Bona Sforza, who detested the new bride. The treaty was renewed on 16 June 1538 in Wrocław by Johannes Dantiscus and the betrothal ceremony took place on 17 July 1538 in Innsbruck. Bona continued to lobby against the marriage and instead proposed Margaret of France to potentially form an alliance with the French against the Habsburgs.

On 5 May 1543, Elizabeth's escorted convoy entered Kraków and was greeted with enthusiasm by both the nobles and the townsfolk. The same day 16-year-old Elizabeth married 22-year-old Sigismund Augustus, whom she met for the first time shortly before marriage vows. The ceremony was performed at the Wawel Cathedral and the wedding continued for two weeks. Bona began to plot against the new queen. As a result, the newly wedded couple decided to reside in Vilnius, far from the royal court.

Despite the initial euphoria demonstrated by royal subjects, the marriage was unsuccessful from the very beginning. Sigismund Augustus did not find Elizabeth attractive and continued to have extramarital affairs with several mistresses, the most famous being Barbara Radziwiłł. Elizabeth was also known to be timid, meek and apprehensive due to strict upbringing. The young and garrulous king was also repulsed by Elizabeth's newly diagnosed epilepsy and subsequent seizures. Only Sigismund the Old and some nobles showed compassion towards the new Queen, who was disregarded by her husband and scorned by Bona. Sigismund Augustus was indifferent to her health condition; when the seizures continued to intensify he abandoned Elizabeth and returned to Kraków to collect her dowry. He also sent for Ferdinand's doctors to travel the long distance from Vienna knowing that Elizabeth was ailing and deteriorating fast. She eventually died unattended and exhausted from the epileptic attacks on 15 June 1545 at the age of 18.

Second marriage
From the outset of his reign, Sigismund Augustus came into collision with the country's privileged nobility, who had already begun curtailing the power of the great families. The ostensible cause of the nobility's animosity to the King was his second marriage, secretly contracted before his accession to the throne, with the Lithuanian, Calvinist and former mistress, Barbara Radziwiłł, the daughter of Hetman Jerzy Radziwiłł. The marriage was announced by the king himself on 2 February 1548 in Piotrków Trybunalski.

The young and beautiful Barbara was despised by Queen Bona, who attempted to annul the marriage at any cost. The agitation was also abundant at Sigismund's first Sejm (parliament) sitting on 31 October 1548 where the deputies threatened to renounce their allegiance unless the new king repudiated Barbara. The nobles portrayed Barbara as an opportunistic prostitute that charmed the king for her own benefit. That perception was shared with Bona Sforza, who decisively eliminated all her rivals by any means to stay in power. The young monarch even considered abdicating. By 1550, when Sigismund summoned his second Sejm, the nobles had begun to be in his favor; the nobility was rebuked by Marshal Piotr Kmita Sobieński, who accused them of attempting to unduly diminish the legislative prerogatives of the Polish Crown. Furthermore, Bona was removed from Wawel and sent to Mazovia where she established her own small courtly entourage.

Unlike her predecessor, Barbara was disliked by the royal court and led a more secluded life with Sigismund Augustus, who was deeply in love with her. On the other hand, she was ambitious, intelligent, perceptive and had an exemplar taste in fashion. She always wore precious pearl necklaces when sitting for portraits. The mutual admiration between Sigismund and Barbara made the relationship "one of the greatest love affairs in Polish history". While still married to Elizabeth, Sigismund Augustus ordered the construction of a secret passage connecting the Royal Castle in Vilnius with the nearby Radziwiłł Palace so that the couple could meet frequently and discreetly.

Due to her unpopularity in Poland, Barbara often expressed her wish to reside permanently in the Grand Duchy of Lithuania. To ease the situation, Sigismund Augustus provided a luxurious lifestyle and expensive gifts for his wife at Wawel Castle since her arrival in Kraków on 13 February 1549. The monarch also granted Barbara several provinces to administer and provide income. Although ambitious and bright, she showed lack of interest in political life, but had some influence over decisions made by Sigismund. This also caused an uproar among the nobility. To avoid an armed rebellion, Sigismund was forced to form an alliance with his former father-in-law, Emperor Ferdinand I. This allowed for Barbara's coronation as Queen of Poland on 7 December 1550 by Primate Mikołaj Dzierzgowski. Queen Bona eventually succumbed to her son's demand and accepted the marriage sending a messenger in 1551 who informed Barbara of her decision.

Since the day Sigismund and Barbara met, she complained of poor health, particularly stomach and abdominal pain. After the coronation her condition deteriorated rapidly. She was tormented by strong fever, diarrhea, nausea and lack of appetite. After careful observation by hired medics, a lump was discovered on her stomach filled with pus. Sigismund Augustus gravely despaired and sent for doctors and even folk healers from the entire country. He personally tended to his sick wife despite her foul smell and dedicated himself when necessary; the king hoped to take Barbara to the hunting castle at Niepołomice and ordered to demolish the small city gate so her carriage could pass freely. However, Barbara died on 8 May 1551 in Kraków after continuous pain and agony. It was her dying wish that she'd be buried in Lithuania, her homeland. The body was transported to Vilnius Cathedral, where she was finally buried on 23 June next to Elizabeth of Austria. Her death was a major blow to Sigismund; he often attended her coffin on foot while being transported to Vilnius in hot weather. Sigismund also became more serious and reserved; he avoided balls, temporarily renounced his mistresses and dressed in black until his death.

The cause of Barbara's death is debatable. Her opponents and family members suggested sexually transmitted diseases due to a number of affairs she had before marrying Sigismund. There were also persistent rumors that she was poisoned by Queen Bona Sforza, who had a long history of eliminating her rivals or enemies quickly and efficiently. However, contemporary historians and experts agree on cervical or ovarian cancer.

Third marriage

The death of Queen Barbara Radziwiłł, five months after her coronation and under distressing circumstances, compelled Sigismund to contract a third, purely political union with his first cousin, the Austrian archduchess Catherine, to avoid an Austro-Russian alliance. She was also the sister of his first wife, Elizabeth, who had died within a year of her marriage to him, before his accession. Catherine, unlike previous queens, was considered dull and obese. Sigismund Augustus found her immensely unattractive despite accepting the marriage and organizing a pompous wedding ceremony on 30 July 1553. On the other hand, Catherine showed resentment towards Sigismund because of how he treated her sister, Queen Elizabeth. She accused him of negligence and indifference during her sudden illness, which caused premature death. The correspondence between the two remained purely formal and political for the remainder of their lives.

Since her coronation, Catherine acted as Austria's puppet at the Polish court; she was tasked with espionage and obtaining important information for the benefit of the Habsburgs. Sigismund Augustus was aware of the scheme, but, by marrying Catherine, he obtained a promise from Austria to stay neutral and abandon plans with Russia. This neutrality was undermined by Catherine's actions, who followed her father's policy and objected the return of John Sigismund Zápolya and Isabella Jagiellon (Sigismund's sister) to Hungary. She would conspire with the Habsburg envoys prior to an audience with the king. She would also dictate what and how the envoys should express their views. When Sigismund Augustus found out of Catherine's intrigues, he sent her to Radom and excluded from political life.

As Sigismund lost all hope of children by his third bride, he was the last male Jagiellon in the direct line so the dynasty was threatened with extinction. He sought to remedy this by adultery with two of the most beautiful of his countrywomen, Barbara Giza and Anna Zajączkowska but was unable to impregnate either of them. The Sejm was willing to legitimize, and acknowledge as Sigismund's successor, any male heir who might be born to him; however, the King remained childless.

The King's marriage was a matter of great political import to Protestants and Catholics alike. The Polish Protestants hoped that he would divorce and remarry and thus bring about a breach with Rome at the very crisis of the religious struggle in Poland. He was not free to remarry until Catherine's death on 28 February 1572, but he followed her to the grave less than six months later.

Health and final years
Unlike his father, Sigismund Augustus was frail and sickly. Shortly before turning 50, his health rapidly declined. Being involved in many affairs and holding a large number of mistresses, historians agree that the king had venereal disease which caused him to be infertile. At 16, he also contracted malaria which further contributed to his inability of producing any offspring. By 1558 Sigismund had gout and since 1568 he also suffered from kidney stones, which triggered immense pain. He employed numerous medics, healers or even quack doctors and imported expensive ointments from Italy. By the end of his life, the king was losing teeth and vigour, possibly due to tuberculosis. Antonio Maria Graziani recalls that Sigismund was unable to keep standing without a cane when greeting Cardinal Giovanni Francesco Commendone.

During spring of 1572, Sigismund Augustus became feverish. Untreated tuberculosis made him feeble and impotent, but he was able to travel to his private retreat in Knyszyn. While at Knyszyn, he corresponded with his diplomats and nobles, highlighting that he was feeling well and hoped to recover. Great Marshal Jan Firlej denied these claims and reported that the king was bleeding severely due to consumption and was troubled by pain in the chest and lumbar.

Sigismund died in Knyszyn on 7 July 1572 at 6 in the afternoon, surrounded by a group of senators and envoys. The official cause of death given by the medics was consumption. His body placed on a catafalque and remained at the nearby Tykocin Castle until 10 September 1573 when it was transported back to Kraków through Warsaw. After transporting the remains of Barbara Radziwiłł from Kraków to Vilnius, Sigismund was building a church in the Vilnius Castle Complex which should have served as his family's mausoleum, however it was still uncompleted in 1572. Consequently, he was laid to rest at the Wawel Cathedral on 10 February 1574. The stately funeral ceremony, attended by his sister Anna Jagiellon, was the last spectacle of its kind in the Kingdom of Poland. No other Polish monarch was buried with such pomp and splendour. His death introduced an elective monarchy in Poland which lasted until the final partition at the end of the 18th century.

Sigismund Augustus was the last male member of the Jagiellonian dynasty. The death of his childless sister, Anna, in 1596 marked the end of the dynasty.

In addition to his family connections, Sigismund II Augustus was allied to the Habsburgs as member of the Order of the Golden Fleece.

Reign
Sigismund's reign was marked by a period of temporary stability and external expansion. He witnessed the bloodless introduction of the Protestant Reformation into Poland and Lithuania, and the peero-cratic upheaval that placed most political power in the hands of the Polish nobility; he saw the collapse of the Knights of the Sword in the north, which led to the Commonwealth's acquisition of Livonia as a Lutheran duchy and the consolidation of Ottoman power in the southeast. A less imposing figure than his father, the elegant and refined Sigismund II Augustus was nevertheless an even more effective statesman than the stern and majestic Sigismund I the Old.

Sigismund II possessed to a high degree the tenacity and patience that seem to have characterized all the Jagiellons, and he added to these qualities a dexterity and diplomatic finesse. No other Polish king seems to have so thoroughly understood the nature of the Polish Sejm and national assembly. Both the Austrian ambassadors and the papal legates testify to the care with which he controlled his nation. According to diplomats, everything went as Sigismund wished and he seemed to know everything in advance. He managed to obtain more funds from the Sejm than his father ever could, and at one of the parliament sittings he won the hearts of the assembled envoys by unexpectedly appearing in a simple grey coat of a Mazovian lord. Like his father, a pro-Austrian by conviction, he contrived even in this respect to carry with him the nation, often distrustful of the Germans. He also avoided serious complications and skirmishes with the powerful Turks.

Livonia
During Sigismund Augustus' reign, Livonia was in political turmoil. His father, Sigismund I, permitted Albert of Prussia to introduce the Protestant Reformation and secularize the southern part of the Teutonic Order State. Albert then established Europe's first Protestant state in the Duchy of Prussia in 1525, but under Polish suzerainty. However, his efforts to introduce Protestantism to the Livonian Brothers of the Sword in the northernmost part of the region was met with fierce resistance and divided the Livonian Confederation. When Albert's brother Wilhelm and Archbishop of Riga attempted to implement a Lutheran church order in his diocese, the Catholic estates rebelled and arrested both Wilhelm and his bishop coadjutor, Christopher, Duke of Mecklenburg.

As Prussia was a tributary state of the Polish Crown, Sigismund Augustus, a Catholic, was forced to intervene in favour of Protestant Albert and his brother Wilhelm. In July 1557 the Polish forces left for Livonia. The armed intervention proved to be successful; the Catholic Livonians surrendered and signed the Treaty of Pozvol on 14 September 1557. The agreement placed most Livonian territories under Polish protection and de facto became part of Poland. Gotthard Kettler, the last Master of the Order, was granted the newly established Duchy of Courland and Semigallia. Wilhelm was restored to his former position as archbishop on Sigismund's demand, with the Lutheran church order being enacted.

The incorporation of Courland into the Polish sphere of influence created an alliance which threatened Russia's plans of expanding into the Baltic coast. Sigismund directed the alliance against Ivan the Terrible to protect lucrative trade routes in Livonia, thus creating a new valid casus belli against the Russian Tsardom. On 22 January 1558, Ivan invaded the Baltic states and started the Livonian War, which lasted 25 years until 1583. Russia's eventual defeat in the war legally partitioned Livonia between Poland (Latvia, southern Estonia) and Sweden (central-northern Estonia). The Polish sector became subsequently known as Polish Livonia or Inflanty; it was settled with colonists from Poland proper resulting in systematic polonisation of these lands.

Northern Seven Years' War
When the Kalmar Union between Sweden and Denmark was disbanded in 1523 due to Swedish resentment of Danish tyranny, Baltic trade became threatened. The port city of Gdańsk (Danzig), Poland's wealthiest city, faced difficulties due to ongoing conflict on the sea and piracy. The capital, Kraków, was also affected as the trade route from the Baltic ran through Gdańsk and along the Vistula river to the southern province of Lesser Poland. Gdańsk, which was privileged with its own army and government, resisted against Sigismund's order of sending privateers and creating the first Polish Admiralty in their city. Most of the deputies in the city council were merchants and tradesmen of German descent or Protestants who were either politically leaning towards Sweden or fighting for the status of an independent 'city state'. 11 Polish privateers sent by Sigismund were eventually executed, which greatly angered the king. Poland then joined Denmark against Sweden for Baltic domination.

The war ended as status quo ante bellum in 1570 with the Treaty of Stettin, which was signed by Bishop Martin Kromer on behalf of Sigismund Augustus. However, the ineffective conflict did have its input in establishing Poland's first registered naval fleet (Naval Commission) in 1568.

Union of Lublin
Sigismund's most striking legacy may have been the Union of Lublin, which united Poland and Lithuania into one state, the Polish–Lithuanian Commonwealth, jointly with German-speaking Royal Prussia and Prussian cities. This achievement might well have been impossible without the monarch's personal approach to politics and ability to mediate.

At first, the treaty was perceived as a threat to Lithuanian sovereignty. Lithuanian magnates were afraid of losing their powers, since the proposed union would lower their rank and status to an equivalent with petty nobility rather than wealthier Polish aristocracy. On the other hand, the unification would provide a strong alliance against Russian (Muscovite) attack from the east. Lithuania was ravaged by the Muscovite-Lithuanian Wars which endured for over 150 years. During the Second War, Lithuania lost 210000 sqmi of its territory to Russia, and the final defeat in the Livonian War would result in the country's incorporation into the Russian Tsardom. Furthermore, the Poles were reluctant to aid Lithuania without a quid pro quo. The most vocal opponent of the union was Sigismund's brother-in-law, Mikołaj "the Red" Radziwiłł (Radvila Rudasis), who viewed the agreement as "peaceful annexation of Lithuania" by Poland. He also resisted polonisation policies which forced ethnic Lithuanians to change their names and native language to Polish or Latin.

As another war with Russia loomed, Sigismund Augustus pressed the members of parliament (Sejm) for the union, gradually gaining more followers due to his persuasive abilities and auspicious diplomacy. The potential union agreement would lead to the eviction of Lithuanian landowners who opposed the transition of territory from multi-ethnic Lithuania to Poland. Such terms were causing an outrage among the most renowned members of Lithuanian upper classes, but Sigismund was decisive and ruthless in this matter. Moreover, the personal union between the two countries created by the marriage of Jadwiga with Jogaila in 1385 was not entirely constitutional. Being the last male member of the Jagiellons, childless Sigismund sought to preserve his dynasty's legacy. The newly proposed constitutional union would create one large Commonwealth state, with one elected monarch who would simultaneously reign over both domains.

The initial Sejm negotiations on unity in January 1569, near the Polish city of Lublin, were futile. The right of Poles to settle and own land in the Grand Duchy was questioned by Lithuanian envoys. Following Mikołaj Radziwiłł's departure from Lublin on 1 March 1569, Sigismund announced the incorporation of then-Lithuanian Podlachia, Volhynia, Podolia and Kiev provinces into Poland, with strong approval from the local Ruthenian (Ukrainian) gentry. Those historic regions, which once belonged to the Kievan Rus', were disputed between Lithuania and Russia. However, the Ruthenian nobles were eager to capitalise on the political or economic potential offered by the Polish sphere and agreed to the terms. Previously, the Kingdom of Ruthenia or "Ukraine" was abolished in 1349, after Poland and Lithuania split modern-day Ukraine in the aftermath of the Galicia–Volhynia Wars. Now, under the Union of Lublin, all Ukrainian and Ruthenian territories which were alien in culture, customs, religion and language to the Polish people would be annexed by Catholic Poland. Strong westernisation and polonisation would follow, including the clandestine suppression of the Ukrainian Eastern Orthodox Church by future King Sigismund III. Ruthenia remained under Polish rule until the Cossack uprisings against Polish domination and the Partitions of Poland, when Ukraine was annexed by the Russian Empire.

The Lithuanians were compelled to return to the Sejm negotiations under Jan Hieronim Chodkiewicz and continue negotiations. The Polish nobility once again pressed for the full incorporation of the Grand Duchy of Lithuania into Poland, however, the Lithuanians disapproved. The parties eventually agreed on a federal state on 28 June 1569 and on 1 July 1569 the Union of Lublin was signed at Lublin Castle, thus establishing the Polish–Lithuanian Commonwealth. Sigismund Augustus ratified the unification act on 4 July, and henceforth governed one of the largest and multicultural countries of 16th-century Europe.

Religion
In comparison to his staunchly Catholic father, Sigismund Augustus paid little attention to the matters of faith and religion. Having a large number of mistresses before, during and after being married, he was viewed by the clergy as an adulterer and libertine. Sigismund was also reasonably tolerant towards minorities and supported nobles of different faith and nationality to be part of the national assembly, the Sejm. He continued his father's policies, but was more accepting of the Protestant Reformation in Poland (only to the status of a minority religion). Several magnates converted to Calvinism or Lutheranism during the Reformation started by Martin Luther and John Calvin, most notably Stanisław Zamoyski, Jan Zamoyski, Mikołaj Rej, Andrzej Frycz Modrzewski, Johannes a Lasco (Jan Łaski) and Mikołaj "the Black" Radziwiłł.

Throughout the 16th century, Frycz Modrzewski advocated for renouncing Rome's authority and establishing a separate and independent Polish Church. His initiative was chiefly inspired by the creation of the Anglican Church by Henry VIII in 1534. Sigismund Augustus was lenient towards the idea, particularly due to the sudden spread of Protestantism among courtiers, advisors, nobles and peasants. Calvinism became especially popular among the upper classes as it promoted democratic freedoms and called for rebellion against absolutism, which the privileged Polish nobility favoured. During the 1555 Sejm session in Piotrków, the nobles intensively discussed the rights of priests in the newly proposed Polish Church and demanded the abolition of celibacy. Some Catholic bishops were supportive of the concepts and acknowledged the need for uniting Poland, Lithuania, Prussia and their vassals under a common religion. Sigismund agreed to the postulates, however, under the condition that Pope Paul IV will be in favour. Instead, Paul IV was enraged that such a proposition emerged for him to accept; he declined and refused to grant consent. Facing potential excommunication, the assembly were forced to abandon their plans. Nevertheless, Protestantism continued to flourish and spread. In 1565, the Polish Brethren came into existence as a Nontrinitarian sect of Calvinism.

One year after Sigismund's death the Warsaw Confederation was adopted as the first European act granting religious freedoms. Despite this, Protestantism in Poland ultimately declined during the fierce Counter-Reformation measures under the despotic and arch-Catholic Sigismund III Vasa, who ruled for nearly 45 years. For instance, the Polish Brethren were banned, hunted down and its leaders executed.

Patronage
Sigismund Augustus carried on with the development of several royal residencies including Wawel, Vilnius Castle, Niepołomice and the Royal Castle in Warsaw. In the 1560s he acquired the Tykocin Castle and rebuilt it in Renaissance style. During the reign of Sigismund Augustus the structure served as a royal residence with an impressive treasury and library as well as the main arsenal of the crown.

Sigismund Augustus was a passionate collector of jewels and gemstones. According to nuncio Bernardo Bongiovanni's relation, his collection was cached in 16 chests. Among the precious items in his possession was Charles V's ruby of 80,000 scudos' worth, as well as the Emperor's diamond medal with Habsburgs Eagle on one side and two columns with a sign Plus Ultra on the other side. In 1571, after the death of his nephew John Sigismund Zápolya, he inherited the Hungarian Crown used by some Hungarian monarchs. A Swedish Crown was also made for him. The Polish king treated those crowns as a family keepsake, and kept them in a private vault in the Tykocin Castle. He had also a sultan's sword of 16,000 ducats' worth, 30 precious horse trappings and 20 different private-use armours. The king's possession included a rich collection of tapestries (360 pieces), commissioned by him in Brussels in the years 1550–1560.

The king enjoyed reading, especially short stories, poems and satires. Under the influence of bishop Piotr Myszkowski, Poland's then greatest writer and poet Jan Kochanowski joined the royal court in 1563. It is uncertain whether Sigismund and Kochanowski were friends, however, Kochanowski's correspondence clearly highlights that the two had close contact and he assisted the monarch at most important occasions, including military maneuvers in Lithuania in 1567. Kochanowski was also present during the signing of Lublin Union in 1569.

Sigismund was fond of foreign craft-makers and employed Italian goldsmiths, jewellers and medalists, very much like his father. One of the more renowned figures brought to Poland was Giovanni Jacopo Caraglio. In Italy, Caraglio was one of the first reproductive printmakers. In Poland, Sigismund tasked him with the production of cameos, medallions, coins and jewellery. Numerous medals and roundels from this period feature the last members of the Jagiellonian dynasty. When Sigismund's mother Bona died in 1557, Sigismund had to collect his inheritance from the Italian estates. On 18 October 1558, the king granted the right to arrange the first regular Polish postal service operating from Kraków to Venice, thus establishing Poczta Polska (Polish Post). All maintenance costs were borne by the Crown and the post was mostly managed by Italians or Germans. Additional couriers travelled between Kraków, Warsaw and Vilnius. Since 1562, the postal route also encompassed Vienna and cities in the Holy Roman Empire, which enabled continuous correspondence with the Habsburgs.

In 1573, the first permanent bridge over the Vistula river in Warsaw and also the longest wooden bridge in Europe at the time was named in Sigismund's honour.

Royal titles

 * Royal titles, in Latin: "Sigismundus Augustus, Dei gratia rex Poloniae, magnus dux Lithuaniae, nec non terrarum Cracoviae, Sandomiriae, Siradiae, Lanciciae, Cuiaviae, Kiioviae, dominus hereditarius Russiae, Woliniae, Prussiae, Masoviae, Podlachiae, Culmensis, Elbingensis, Pomeraniae, Samogitiae, Livoniae etc. dominus et heres."
 * English translation: "Sigismund Augustus, by the Grace of God, King of Poland, Grand Duke of Lithuania, Lord and heir of the Lands of Kraków, Sandomierz, Sieradz, Łęczyca, Kuyavia, Kiev, Hereditary Lord of Ruthenia, Volhynia, Prussia, Masovia, Podlaskie, Culmer Land, Elbing, Pomerania, Samogitia, Livonia etc. Lord and heir"

title: Sigismund II Augustus


text:
Princeton Plasma Physics Laboratory

Princeton Plasma Physics Laboratory (PPPL) is a United States Department of Energy national laboratory for plasma physics and nuclear fusion science. Its primary mission is research into and development of fusion as an energy source. It is known for the development of the stellarator and tokamak designs, along with numerous fundamental advances in plasma physics and the exploration of many other plasma confinement concepts.

PPPL grew out of the top-secret Cold War project to control thermonuclear reactions, called Project Matterhorn. The focus of this program changed from H-bombs to fusion power in 1951, when Lyman Spitzer developed the stellarator concept and was granted funding from the Atomic Energy Commission to study the concept. This led to a series of machines in the 1950s and 1960s. In 1961, after declassification, Project Matterhorn was renamed the Princeton Plasma Physics Laboratory.

PPPL's stellarators proved unable to meet their performance goals. In 1968, Soviet's claims of excellent performance on their tokamaks generated intense scepticism, and to test it, PPPL's Model C stellarator was converted to a tokamak. It verified the Soviet claims, and since that time, PPPL has been a worldwide leader in tokamak theory and design, building a series of record-breaking machines including the Princeton Large Torus, TFTR and many others. Dozens of smaller machines were also built to test particular problems and solutions, including the ATC, NSTX, and LTX.

PPPL is located on Princeton University's Forrestal Campus in Plainsboro Township, New Jersey.

Formation
In 1950, John Wheeler was setting up a secret H-bomb research lab at Princeton University. Lyman Spitzer, Jr., an avid mountaineer, was aware of this program and suggested the name "Project Matterhorn".

Spitzer, a professor of astronomy, had for many years been involved in the study of very hot rarefied gases in interstellar space. While leaving for a ski trip to Aspen in February 1951, his father called and told him to read the front page of the New York Times. The paper had a story about claims released the day before in Argentina that a relatively unknown German scientist named Ronald Richter had achieved nuclear fusion in his Huemul Project. Spitzer ultimately dismissed these claims, and they were later proven erroneous, but the story got him thinking about fusion. While riding the chairlift at Aspen, he struck upon a new concept to confine a plasma for long periods so it could be heated to fusion temperatures. He called this concept the stellarator.

Later that year he took this design to the Atomic Energy Commission in Washington. As a result of this meeting and a review of the invention by scientists throughout the nation, the stellarator proposal was funded in 1951. As the device would produce high-energy neutrons, which could be used for breeding weapon fuel, the program was classified and carried out as part of Project Matterhorn. Matterhorn ultimately ended its involvement in the bomb field in 1954, becoming entirely devoted to the fusion power field.

In 1958, this magnetic fusion research was declassified following the United Nations International Conference on the Peaceful Uses of Atomic Energy. This generated an influx of graduate students eager to learn the "new" physics, which in turn influenced the lab to concentrate more on basic research.

The early figure-8 stellarators included: Model-A, Model-B, Model-B2, Model-B3. Model-B64 was a square with round corners, and Model-B65 had a racetrack configuration. The last and most powerful stellarator at this time was the "racetrack" Model C (operating from 1961 to 1969).

Tokamak
By the mid-1960s it was clear something was fundamentally wrong with the stellarators, as they leaked fuel at rates far beyond what theory predicted, rates that carried away energy from the plasma that was far beyond what the fusion reactions could ever produce. Spitzer became extremely skeptical that fusion energy was possible and expressed this opinion in very public fashion in 1965 at an international meeting in the UK. At the same meeting, the Soviet delegation announced results about 10 times better than any previous device, which Spitzer dismissed as a measurement error.

At the next meeting in 1968, the Soviets presented considerable data from their devices that showed even greater performance, about 100 times the Bohm diffusion limit. An enormous argument broke out between the AEC and the various labs about whether this was real. When a UK team verified the results in 1969, the AEC suggested PPPL to convert their Model C to a tokamak to test it, as the only lab willing to build one from scratch, Oak Ridge, would need some time to build theirs. Seeing the possibility of being bypassed in the fusion field, PPPL eventually agreed to convert the Model C to what became the Symmetric Tokamak (ST), quickly verifying the approach.

Two small machines followed the ST, exploring ways to heat the plasma, and then the Princeton Large Torus (PLT) to test whether the theory that larger machines would be more stable was true. Starting in 1975, PLT verified these "scaling laws" and then went on to add neutral beam injection from Oak Ridge that resulted in a series of record-setting plasma temperatures, eventually topping out at 78 million kelvins, well beyond what was needed for a practical fusion power system. Its success was major news.

With this string of successes, PPPL had little trouble winning the bid to build an even larger machine, one specifically designed to reach "breakeven" while running on an actual fusion fuel, rather than a test gas. This produced the Tokamak Fusion Test Reactor, or TFTR, which was completed in 1982. After a lengthy breaking-in period, TFTR began slowly increasing the temperature and density of the fuel, while introducing deuterium gas as the fuel. In April 1986, it demonstrated a combination of density and confinement, the so-called fusion triple product, well beyond what was needed for a practical reactor. In July, it reached a temperature of 200 million kelvins, far beyond what was needed. However, when the system was operated with both of these conditions at the same time, a high enough triple product and temperature, the system became unstable. Three years of effort failed to address these issues, and TFTR never reached its goal. The system continued performing basic studies on these problems until being shut down in 1997. Beginning in 1993, TFTR was the first in the world to use 1:1 mixtures of deuterium–tritium. In 1994 it yielded an unprecedented 10.7 megawatts of fusion power.

Later designs
In 1999, the National Spherical Torus Experiment (NSTX), based on the spherical tokamak concept, came online at the PPPL.

Odd-parity heating was demonstrated in the 4 cm radius PFRC-1 experiment in 2006. PFRC-2 has a plasma radius of 8 cm. Studies of electron heating in PFRC-2 reached 500 eV with pulse lengths of 300 ms.

In 2015, PPPL completed an upgrade to NSTX to produce NSTX-U that made it the most powerful experimental fusion facility, or tokamak, of its type in the world.

In 2017, the group received a Phase II NIAC grant along with two NASA STTRs funding the RF subsystem and superconducting coil subsystem.

In 2024, the lab announced MUSE, a new stellarator. MUSE uses rare-earth permanent magnets with a field strength that can exceed 1.2 teslas. The device uses quasiaxisymmetry, a subtype of quasisymmetry. The research team claimed that its use of quasisymmetry was more sophisticated than prior devices. Also in 2024, PPL announced a reinforcement learning model that could forecast tearing mode instabilities up to 300 milliseconds in advance. That is enough time for the plasma controller to adjust operating parameters to prevent the tear and maintain H-mode performance.

Directors
In 1961 Gottlieb became the first director of the renamed Princeton Plasma Physics Laboratory.
 * 1951–1961: Lyman Spitzer, director of Project Matterhorn
 * 1961–1980: Melvin B. Gottlieb
 * 1981–1990: Harold Fürth
 * 1991–1996: Ronald C. Davidson
 * 1997 (January–July): John A. Schmidt, interim director
 * 1997–2008: Robert J. Goldston
 * 2008–2016: Stewart C. Prager
 * 2016–2017: Terrence K. Brog (interim)
 * 2017–2018: Richard J. Hawryluk (interim)
 * 2018–present: Sir Steven Cowley, 1 July 2018

Other domestic and international research activities
Laboratory scientists are collaborating with researchers on fusion science and technology at other facilities, including DIII-D in San Diego, EAST in China, JET in the United Kingdom, KSTAR in South Korea, the LHD in Japan, the Wendelstein 7-X (W7-X) device in Germany, and the International Thermonuclear Experimental Reactor (ITER) in France.

PPPL manages the U.S. ITER project activities together with Oak Ridge National Laboratory and Savannah River National Laboratory. The lab delivered 75% of components for the fusion energy experiment's electrical network in 2017 and has been leading the design and construction of six diagnostic tools for analyzing ITER plasmas. The PPPL physicist Richard Hawryluk served as ITER Deputy Director-General from 2011 to 2013. In 2022, PPPL staff developed with researchers from other national labs and universities over several months a US ITER research plan during the joint Fusion Energy Sciences Research Needs Workshop.

Staff are applying knowledge gained in fusion research to a number of theoretical and experimental areas including materials science, solar physics, chemistry, and manufacturing. PPPL also aims to speed the development of fusion energy through the development of an increased number of public-private partnerships.

Plasma science and technology

 * Beam Dynamics and Nonneutral Plasma
 * Laboratory for Plasma Nanosynthesis (LPN)

Theoretical plasma physics

 * DOE Scientific Simulation Initiative
 * U.S. MHD Working Group
 * Field Reversed Configuration (FRC) Theory Consortium
 * Tokamak Physics Design and Analysis Codes
 * TRANSP Code
 * National Transport Code Collaboration (NTCC) Modules Library

Transportation
Tiger Transit's Route 3 runs to Forrestal Campus and terminates at PPPL.

title: Princeton Plasma Physics Laboratory


text:
Talk:July 6

Malawi
Malawi seems to have two holidays on the same day; also, does anyone know for sure whether Principia was published today or on July 5? Vicki Rosenzweig

Dengue Fever in Cuba
I notice that the article about Dengue Fever does not mention that the disease has apparently been weaponized given the outbreak in Cuba. I think either the Dengue Fever article should be updated (beyond my competance) or an article further explaining the July 6, 1981 attack on Cuba should be provided (again, not my purview). — Preceding unsigned comment added by 24.62.24.148 (talk • contribs) 22:00, 6 July 2005

International Kissing Day
u should add that, the 6 July is celebrated worldwide as the "day of kissing" — Preceding unsigned comment added by 87.183.247.30 (talk • contribs) 18:05, 29 April 2007
 * should be deleted. "unofficial".  --142.163.195.90 (talk) 22:16, 5 July 2021 (UTC)
 * agreed--142.163.195.12 (talk) 15:17, 29 June 2022 (UTC)

Ranjit Singh
1799 - Ranjit Singh's 25,000 men start their march towards Lahore.

Please see the year of birth of Ranjit singh is 1780..--sunil 00:27, 4 July 2007 (UTC)

Removed
Entry for bikini puts the date of introduction at July 5, 1946. — Preceding unsigned comment added by 208.27.203.127 (talk • contribs) 14:02, 6 July 2007
 * 1946 - The Bikini was first made, worn, and created.

Dalai lama
Why is there a birth entry under the name Dalai Lama, this is a title like The Pope or The Archbishop of Canterbury. The entry should be under the man's name, unfortunately not supported by an article named Tensin Gyatso, only a mysterious redirect. Pope works much better as a model. Richard Avery (talk) 06:34, 6 July 2014 (UTC)

Dollar
Right, I’ve removed the reference to Congress approving the dollar: as Wikipedia’s own article says this was on 8th August … ! — Preceding unsigned comment added by Cuddy2977 (talk • contribs) 13:34, 1 July 2015 (UTC)

Birth and death entries
Continuing the ongoing effort to reduce the size of the Births and Deaths sections to make them manageable, I've removed some celebrities with few or no articles in other wikipedias, moving the entries to the appropriate Year in Topic article if they were not already present. This is in accordance with the guidelines. Deb (talk) 15:09, 5 July 2015 (UTC)

1940 – Jeannie Seely, Legendary Grammy Award winning Country Music singer-songwriter and Grand Ole Opry member
Is this a standard entry format? --Stuartkau (talk) 12:06, 6 July 2016 (UTC)

Is Jane Gale (sister of June) really alive? 177.158.192.133 (talk) 02:54, 11 December 2017 (UTC)

External links modified (January 2018)
Hello fellow Wikipedians,

I have just modified one external link on July 6. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://archive.is/20121208135640/http://www1.sympatico.ca/cgi-bin/on_this_day?mth=Jul&day=06 to http://www1.sympatico.ca/cgi-bin/on_this_day?mth=Jul&day=06

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 17:41, 21 January 2018 (UTC)

"National Fried Chicken Day"
industrial promotion. should be deleted. --142.163.195.90 (talk) 22:17, 5 July 2021 (UTC)
 * Thanks, done. Deb (talk) 08:37, 6 July 2021 (UTC)

Cayman Islands
OK: this articles tells us its Constitution Day in the Caymans Islands.

However, the article Public holidays in the Cayman Islands tells us the holiday is marked on 2nd July.

Is it possible an editor could correct this, please?

I’ve tried similar revisions, myself, only to see them reverted.

Cuddy2977 (talk) 19:20, 26 June 2022 (UTC)

Anti-Jewish legislation?
page contains this statement:

"1939 – Anti-Jewish legislation in prewar Nazi Germany closes the last remaining Jewish enterprises."

However the article it links to contains no such account for July 6 1939.

Which one is wrong? 2600:1700:5DD:310:8989:13D1:AA15:7538 (talk) 01:37, 6 July 2024 (UTC)

title: Talk:July 6


text:
Battering ram

A battering ram is a siege engine that originated in ancient times and was designed to break open the masonry walls of fortifications or splinter their wooden gates. In its simplest form, a battering ram is just a large, heavy log carried by several people and propelled with force against an obstacle; the ram would be sufficient to damage the target if the log were massive enough and/or it were moved quickly enough (that is, if it had enough momentum). Later rams encased the log in an arrow-proof, fire-resistant canopy mounted on wheels. Inside the canopy, the log was swung from suspensory chains or ropes. Rams proved effective weapons of war because at the time wall-building materials such as stone and brick were weak in tension, and therefore prone to cracking when impacted with force. With repeated blows, the cracks would grow steadily until a hole was created. Eventually, a breach would appear in the fabric of the wall, enabling armed attackers to force their way through the gap and engage the inhabitants of the citadel.

The introduction in the later Middle Ages of siege cannons, which harnessed the explosive power of gunpowder to propel weighty stone or iron balls against fortified obstacles, spelled the end of battering rams and other traditional siege weapons. Smaller, hand-held versions of battering rams are still used today by law enforcement officers and military personnel to break open locked doors.

A capped ram is a battering ram that has an accessory at the head (usually made of iron or steel and sometimes punningly shaped into the head and horns of an ovine ram) to do more damage to a building. It was much more effective at destroying enemy walls and buildings than an uncapped ram but was heavier to carry.

Design
The earliest depiction of a possible battering ram is from the tomb of the 11th Dynasty noble Khety, where a pair of soldiers advance towards a fortress under the protection of a mobile roofed structure, carrying a long pole that may represent a simple battering ram.

During the Iron Age, in the ancient Middle East and Mediterranean, the battering ram's log was slung from a wheeled frame by ropes or chains so that it could be made more massive and be more easily bashed against its target. Frequently, the ram's point would be reinforced with a metal head or cap while vulnerable parts of the shaft were bound with strengthening metal bands. Vitruvius details in his text De architectura that Ceras the Carthaginian was the first to make a ram with a wooden base with wheels and a wooden superstructure, with the ram hung within. This structure moved so slowly, however, that he called it the testudo (Latin for "tortoise").

Another type of ram was one that maintained the normal shape and structure, but the support beams were instead made of saplings that were lashed together. The frame was then covered in hides as normal to defend from fire. The only solid beam present was the ram that was hung from the frame. The frame itself was so light that it could be carried on the shoulders of the men transporting the ram, and the same men could beat the ram against the wall when they reached it.

Many battering rams had curved or slanted wooden roofs and side-screens, covered in protective materials, usually fresh wet hides. These canopies reduced the risk of the ram being set on fire, and protected the operators of the ram from arrow and spear volleys launched from above.

An image of an Assyrian battering ram depicts how sophisticated attacking and defensive practices had become by the 9th century BC. The defenders of a town wall are trying to set the ram alight with torches and have also put a chain under it. The attackers are trying to pull on the chain to free the ram, while the aforementioned wet hides on the canopy provide protection against the flames.

By the time the Kushites made their incursions into Egypt, c. 715 BC, walls, siege tactics and equipment had undergone many changes. Early shelters protecting sappers armed with poles trying to breach mudbrick ramparts gave way to battering rams.

The first confirmed use of rams in the Occident happened from 503 to 502 BC when Opiter Verginius became consul of the Romans during the fight against Aurunci people: "The following consuls, Opiter Virginius and Sp. Cassius, first endeavored to take Pometia by storm, and afterwards by raising battering rams (vineae) and other works."

The second known use was in 427 BC, when the Spartans besieged Plataea. The first use of rams within the Mediterranean Basin, featuring in this case the simultaneous employment of siege towers to shelter the rammers from attack, occurred on the island of Sicily in 409 BC, at the Selinus siege. Defenders manning castles, forts or bastions would sometimes try to foil battering rams by dropping obstacles in front of the ram, such as a large sack of sawdust, just before the ram's head struck a wall or gate, or by using grappling hooks to immobilize the ram's log. Alternatively, the ram could be set ablaze, doused in fire-heated sand, pounded by boulders dropped from battlements or invested by a rapid sally of troops.

Some battering rams were not slung from ropes or chains, but were instead supported by rollers. This allowed the ram to achieve a greater speed before striking its target, making it more destructive. Such a ram, as used by Alexander the Great, is described by Vitruvius.

Alternatives to the battering ram included the drill, the sapper's mouse, the pick, the siege hook, and the hunting ram. These devices were smaller than a ram and could be used in confined spaces.

Notable sieges
Battering rams had an important effect on the evolution of defensive walls, which were constructed ever more ingeniously in a bid to nullify the effects of siege engines. Historical instances of the usage of battering rams in sieges of major cities include:
 * The destruction of Jerusalem by the Romans
 * The Crusades
 * The Sack of Rome (410)
 * The various sieges of Constantinople

There is a popular myth in Gloucester, England that the well known children's rhyme, Humpty Dumpty, is about a battering ram used in the siege of Gloucester in 1643, during the Civil War. However, the story is almost certainly untrue; during the siege, which lasted only one month, no battering rams were used, although many cannons were. The idea seems to have originated in a spoof history essay by Professor David Daube written for The Oxford Magazine in 1956, which was widely believed despite obvious improbabilities (e.g., planning to cross the River Severn by running the ram down a hill at speed, although the river is about 30 m (100 feet) wide at this point).

Modern use
Battering rams still have a use in modern times. Police forces often employ small, one-man or two-man metal rams, known as enforcers, for forcing open locked portals or effecting a door breaching. Modern battering rams sometimes incorporate a pneumatic cylinder and piston driven by compressed air, which are triggered by striking a hard object and enhance the momentum of the impact significantly.

title: Battering ram