text:
Etisalat by e&

Emirates Telecommunications Group Company PJSC, doing business as etisalat and, is a UAE state-owned telecommunications company. It is the 18th largest mobile network operator in the world by number of subscribers.

Having a fixed monthly rate depending on speedOn 31 December 2021, Etisalat reported consolidated revenue of AED 53.3 billion and net profits of AED 11.1 billion. The total market capitalization of the company currently is AED329 billion. In May 2023, Etisalat reported revenue of AED13 billion for Q1.

Etisalat is one of the Internet hubs in the Middle East (AS8966), providing connectivity to other telecommunications operators in the region. It is also the largest carrier of international voice traffic in the Middle East and Africa and the 12th largest voice carrier in the world. As of October 2008, Etisalat has 510 roaming agreements covering 186 countries and enabling BlackBerry, 3G, GPRS and voice roaming. Etisalat operates Points of Presence (PoP) in New York, London, Amsterdam, Frankfurt, Paris, and Singapore. In December 2011 Etisalat announced the commercial launch of Etisalat 4G LTE Network. In May 2018 Etisalat announced the commercial launch of Etisalat 5G LTE Network, becoming the first telecom operator in the Middle East and North Africa (MENA) region to do so. Etisalat also has "check your mobile number" service code for its user by dialing *101#.

On 24 February 2022, Etisalat Group launched a new brand identity called e&. The group also announced that it will keep the previous branding identity in the UAE and internationally.

History
Etisalat was founded in 1976 as a joint-stock company between International Aeradio Limited, a British Company, and local partners. In 1983, the ownership structure changed – United Arab Emirates government held a 60% share in the company and the remaining 40% were publicly traded.

In 1991, the UAE central government issued Federal Law No. 1, which gave the corporation the right to provide the telecommunications wired and wireless services in the country and between UAE and other countries. It also gave the firm the right to issue licenses for owning, importing, manufacturing, using, or operating telecommunication equipment. This practically gave Etisalat both regulatory and control powers, which completed the monopoly of the telecom giant in the UAE. In order to safeguard the country's economic development, the law made provisions for the development of the telecommunication sector in the country.

The increase of exchange lines from 36,000 in 1976 to more than 737,000 in 1998 was one of the important indicators of Etisalat network's growth and development. Today Etisalat stands 140th among the Financial Times Top 500 Corporations in the world in terms of market capitalisation, and is ranked by The Middle East magazine as the 6th largest company in the Middle East in terms of capitalization and revenues. The Corporation is the largest contributor outside the oil sector to the development programmes of the UAE Federal Government. Etisalat has also won accolades from across the region for its nationalization programme. In November 2013, it was also announced that Etisalat would be the official sponsor of Cyprus First Division side Anorthosis Famagusta.

e&

e& is headquartered in Abu Dhabi and includes three regional offices – Abu Dhabi, Dubai, and Northern Emirates. The Northern Emirates regional center is based in Sharjah and covers the telecom's operations in the emirates of Ajman, Umm Al Quwain, Fujairah, and Ras Al Khaimah. In the UAE, e& operates where mobile penetration is already among the highest in the world "200%", Etisalat became known for its efforts to roll out its Fibre-To-The-Home (FTTH) network in the UAE. By the end of 2009, Etisalat had completed the FTTH roll-out for 85% of households in Abu Dhabi, positioning the UAE's capital as the first in the world to be covered by fibre.

Some of the Internet services for home users that Etisalat offers include:
 * 3G Mobile Internet access
 * 4G Mobile Internet access
 * Broadband Internet services (Al Shamil and eLife )
 * Prepaid and post-paid dialup Internet access
 * Cloud gaming services in partnership with Gamestream

e& also operates iZone, a system of Wi-Fi hotspots in central locations, such as shopping malls, restaurants, and sheesha cafes. iZone can be accessed by either purchasing prepaid cards or using an existing account. Dial-up and ISDN Internet access services are billed by the hour, whereas the domestic and residential cable and DSL connections have a fixed monthly rate depending on speed. Etisalat has launched different internet packages for residential customers such as; Elife 10G and 5G, Ultra Fusion, and eLife Family. Other Internet links, aimed at business users, have traffic utilization plans and relatively high rates when exceeding the allocated bandwidth quota. This has caused bad publicity for Etisalat and is a major source of criticism.

In addition to its telecommunication service provider and carrier units, e& incorporates a number of additional non-telecom business units under the umbrella of Etisalat Services Holding LLC. These units support the company's operations and even provide services to other operators and organizations in the UAE, namely: training and consultancy services (Etisalat Academy ), SIM/smart card manufacturing and payment solutions (Ebtikar ), data clearing house services (EDCH ), peering/voice and data transit (Emirates Internet Exchange – EMIX ), call center (The Contact Centre ), cable TV (eVision ), facilities management (EFM), as well as submarine cable laying services (eMarine ).

Etisalat is a major investor in Thuraya (34.5%), a satellite geo-mobile communication systems provider. In 2006 Etisalat started a major restructuring program that resulted in the de-merger of many of its non-core business units operating under the telecom's centralized and direct management; core services were consolidated and streamlined, reflecting the company's shift from a technology-driven telecom to a customer-focused services provider. As part of the program, Etisalat launched a re-branding campaign, releasing a new corporate logo and identity in May 2006. The restructuring culminated in the incorporation of Etisalat Services Holding LLC, which as of 2008 oversees the operation of Etisalat's non-telecom business units with huge success stories. On 27 March 2016, Saleh Al Abdooli was appointed the Group CEO, extending his responsibility to international operations. Al Abdooli resigned from the organization for personal reasons in May 2020 and Hatem Dowidar was appointed as the interim Group CEO who was later confirmed as the Group CEO on 16 December 2020.

On 1 June 2013, Etisalat introduced free local and national HD calls across the UAE. Later that week, corporate, private, public, and government sectors in the country were provided with better business IT solutions when Etisalat launched its first cloud service in the UAE.

International presence
Etisalat International Investments was the business unit of Etisalat that operated telecom operations outside the UAE and managed the corporation's stakes in telecommunications carriers in Afghanistan, Egypt, Niger, Saudi Arabia, Sri Lanka and Pakistan. The International Investments unit, and its management team, were re-structured into Etisalat Group, and Ahmad Abdulkarim Julfar was appointed as Group CEO in 2011, followed by Saleh Al Abdooli in 2016.

As of July 2021, Etisalat has presence and operations in 15 countries outside the United Arab Emirates.

As of 2023, Etisalat owns a stake of 14.6% in Vodafone Group one of Europe's largest telecommunication groups. In 2024, the British government warned that e&’s association with Vodafone poses a national security risk. Robert Buckland and Oliver Dowden also urged for measures to address national security concerns. They also asked for the establishment of an independent committee to monitor the risks associated with the stake held by e& in Vodafone. Dowden said the committee should consist of Vodafone employees, while Buckland said the it should be independent of both e& and Vodafone. Buckland said the committee members should be experts in national security, telecoms and human rights, pointing at the UAE’s “history of repressive activity and espionage”.

Etisalat also has a stake in PPF Telecom Group with a percentage of 50.1% which is active in Bulgaria, Hungary, Serbia and Slovakia as a telecommunications provider. In June 2024, Brussels announced its first anti-subsidy investigation, targeting e&’s €2.2bn deal to acquire PPF group’s telecoms assets that was approved by national competition regulators. The European commission was concerned that to complete the acquisition, e& received state funds, amounting to unfair subsidies. Another concern was if the state funds would allow E& to outperform the EU rivals and undermine the competition.

Mobily – Saudi Arabia
One of Etisalat's first international investments was the bid to become the second mobile services operator in Saudi Arabia. Mobily, the brand name of Etihad Etisalat founded in 2005 is currently the second largest mobile service provider in Saudi Arabia with over 20 million subscribers. In less than 6 months the company launched services in 32 cities, Mobily brings coverage to 79.2 percent of the population. Mobily was also the first to build in the shortest period the fastest 3G network in the Kingdom.

Maroc Telecom – Morocco
In July 2013, Vivendi announced it would sell its 53% stake in Maroc Telecom to Etisalat for around billion. Maroc Telecom joined Etisalat Group in 2014 offering telecom and ICT products and services including fixed line, mobile, internet and television. The telecom company is the first global telecom operator in Morocco.

PTCL – Pakistan
Pakistan Telecommunication Company Ltd (PTCL) is the country's largest and multi-service telecom carrier. Etisalat acquired PTCL in 2005 with 26 percent shares including management control from the Government of Pakistan as part of a large privatization initiative.

Etisalat by e& - Egypt
In July 2006, a consortium led by Etisalat was granted the rights to develop Egypt's third mobile network, with a winning bid of £E16.7 billion (EUR €2.29 billion). The venture, Etisalat by e& - Egypt, competes with existing service providers Vodafone and Orange. On 12 September 2006, it was announced that the network would be built by Ericsson of Sweden, and Huawei of China, at a cost of approximately US billion.

Etisalat Egypt's network covers and serves over 99% of the population in Egypt, through more than 6,000 base stations, Etisalat Egypt was the first to launch 3.75G in Egypt and the first operator to launch video call services in Egypt.

Etisalat Afghanistan
Etisalat Afghanistan was launched in 2007 after the UAE telecom operator won the license to operate as the fourth mobile services provider in the Islamic Republic of Afghanistan.

The operator rapidly became the fastest-growing telecommunications service provider in the country. Etisalat Afghanistan has invested over US million in the Afghan telecom industry, and it is wholly owned by Etisalat Group. In 2012, Etisalat won a 3G license in Afghanistan and launched the first 3G services in the history of Afghanistan.

Etisalat shares 60 to 70 mobile towers with government-owned Afghan Telecom, which seeks to grow its five percent market share.

Mauritel – Mauritania
Mauritel is the leading telecommunications company in Mauritania. Mauritel maintains a market share stabilized at around 60% of the population.

Mauritanian Telecommunications Company (Mauritel) Mauritel, which is 41.2% indirectly owned by Maroc Telecom of Morocco, has reportedly renewed its mobile license in the African country for a further ten years.

Sotelma – Mali
The former incumbent telco Sotelma (branded Malitel) was sold by the Government and ended up in the hands of Maroc Telecom. With the sale of Maroc Telecom, its ownership passed onto Etisalat.

Sotelma provides local and international fixed line telephony, internet, mobile telephone, and other telecom services. Its mobile service subsidiary is Malitel, with more than 6 million customers.

Moov – West Africa
In Africa, Etisalat acquired 50% of Atlantique Telecom's shares in April 2005. Based in the Ivory Coast, AT owns mobile operators in Benin, Burkina Faso, Togo, Niger, Central African Republic, Gabon and Côte d'Ivoire. In 2007, Etisalat increased its shares in AT to 70% and again in May 2008, to 82%.

Etisalat Group's brand MOOV operates throughout West Africa, in Benin, Togo, Gabon, Niger, Central Africa, Burkina Faso (as ONATEL) and Côte d'Ivoire, Serving over 50 million people. MOOV covers on average 60% of the populated areas in each of its countries of operations.

Canar – Sudan
Etisalat is one of the founding partner companies of Canar Telecom, a fixed-line telecom services operator. In September 2007 Etisalat has raised its stake in Canar from 37% to 82% at an estimated cost of AED 584.17 million (US million).

Canar was launched on 27 November 2005. The operator is reported to use NGN and Wireless Local Loop (WLL) technologies for its voice, data, internet, and multimedia services. Canar is one of the first operators in Africa to use an NGN network core. In 2016, Etisalat made an exit from the Sudanese market by selling its 92.3% share to the Bank of Khartoum for AED349.6 million.

Etisalat Nigeria
Etisalat Nigeria launched one of the first major broadband services in the country – EasyBlaze. The company is known for its innovative products and services such as the Eco Sim and the first network to offer special numbers to Nigerians as their mobile numbers via the 0809uchoose campaign.

From 2012 to 2015, Etisalat Nigeria hosted the Etisalat Prize for Innovation, established to promote African Internet expansion.

In April 2013, Etisalat Nigeria announced it would invest million to expand its network, enabling further potential market growth of 17%. In June 2013, it launched the Etisalat Prize for Literature the first pan-African prize for debut published writers.

In October 2016, Etisalat Nigeria announced 4G LTE with a frequency band 3 (1800 MHz). Speed test results indicate 28 Mbit/s download and 11 Mbit/s upload. This LTE network currently covers some parts of Lagos and Abuja.

In March 2017, Nigeria's telecoms regulator pushed for talks to halt takeover attempts by Etisalat creditors and reschedule its outstanding bln loan. In July 2017, Etisalat withdrew from the market after its debt was not repaid or rescheduled. The local operator has renamed itself 9mobile.

9mobile, is a Nigerian private limited liability company. EMTS acquired a Unified Access Service License from the Nigerian Communications Commission in 2007. The License enables EMTS to provide Fixed Telephony (wired or wireless), Digital Mobile Services, International Gateway Services, and National/Regional Long Distance Services in addition to spectrum assignments in the 900 and 1800 MHz bands. The Current managing director and chief executive officer of 9mobile is Mr Bode Olusanya.

Etisalat Sri Lanka
Etisalat acquired the Sri Lankan Operation of Millicom International Cellular (MIC), Tigo (Sri Lanka) on 16 October 2009. The acquisition was completed with a total enterprise value of million, out of which  million was in cash.

Tigo (Sri Lanka) under the brand name CELLTEL started operations in June 1989 on a Motorola TACS system and was the first cellular operator in Sri Lanka as well as South Asia. In January 2007, Millicom replaced the local CELLTEL brand with Tigo, their international brand. In February 2010, Tigo was rebranded as Etisalat.

Etisalat Lanka operates a GSM/EDGE supported network using 900 / 1800 MHz. The company on 5 May 2011 launched HSPA+ services over 2100 MHz, becoming the first LTE ready mobile network in the country. Dual Carrier HSPA+ services were launched on 15 August 2012 by Etisalat Sri Lanka, the first operator in South Asia to do so.

Etisalat Lanka was recently mentioned in the UNCTAD Information Economy Report of 2012 for the Android Eco System it had been able to develop in Sri Lanka. It was commended for its inclusive policy and several other innovations done in the market such as the AppZone (Sri Lanka's first independent 3rd party app store and the Book Hub, Sri Lanka's first eBook store) Many governments are now looking at this eco system and how it can too be implemented in their respective countries.

In April 2018 CK Hutchison Holdings and Etisalat Group have entered into a definitive agreement to merge their mobile telecommunications businesses in Sri Lanka. Upon completion of the transaction, CKHH Group will have the majority and controlling stake in the combined entity. CK Hutchison completed the acquisition of Etisalat Lanka on 30 November 2018.

VoIP ban
The United Arab Emirates blocks many popular voice over IP services like Skype. The only licensed VoIP service is BOTIM, which is operated by Etisalat.

BlackBerry controversy
In July 2009, Etisalat pushed an update to BlackBerry devices operating on the telecom's national network, citing performance improvements. However, it was later discovered that the update contained eavesdropping software, developed by the US-based software development company SS8, which specializes in electronic surveillance. It is reported that the software enabled the company to monitor and forward communications on BlackBerry devices to their servers. Research in Motion, BlackBerry's developer, acknowledged that the patch was a form of spyware, and issued a removal patch on 20 July.

On 27 December 2009, both Etisalat and du have been mandated by the UAE telecom regulator to start filtering BlackBerry users' web access and block illegal content. Due to concerns with the security and the provisioning of legal interception for Blackberry non-voice services, on 1 August 2010, the Telecommunication Regularity Authority of the UAE instructed Etisalat that all Blackberry e-mail, internet and messenger functions must be suspended on 1 October 2010. However, an agreement between Blackberry's developer Research in Motion and UAE's telecom regulator has been reached, and the announced BlackBerry services suspension has been canceled.

Etisalat Iran
In January 2009 Etisalat in consortium with Tamin Telecom (a subsidiary of the Iranian Social Security Organization (SSO)) won the bid for running the third mobile services operator in the Islamic Republic of Iran. The license included an exclusive two-year agreement for 3G services provisioning, but in Sep 2009 the license was revoked and given to its local partner, Tamin Telecom.

Etisalat had planned to invest over billion (AED 18.39 billion) over a period of five years, but following the license suspension all plans for launching operations in Iran have been put on hold.

Etisalat India
In 2009, Etisalat announced that its Indian unit, erstwhile Swan Telecom (owned by Dynamix Balwas Realty and Reliance Communications), headquartered in Mumbai, is renamed to Etisalat DB Telecom India Pvt. Ltd. The business unit has been awarded Unified Services Access License in 15 telecom circles (Andhra Pradesh, Delhi, Gujarat, Haryana, Karnataka, Kerala, Maharashtra, Mumbai, Punjab, Rajasthan, Tamil Nadu (including Chennai), Uttar Pradesh (East), Uttar Pradesh (West), Madhya Pradesh and Bihar). The brand name was "Cheers Mobile".

In April 2010, Etisalat began signal testing in Chennai [IND 922], Delhi & NCR [IND 913], Maharashtra & Goa [IND 919], Mumbai [IND 916], and Gujarat [IND 914]. In May 2010, Etisalat was in talks to buy a 25% stake in Reliance Communications, but the deal was not finalised.

In 2010, following the billion 2G spectrum case, Etisalat DB, the Indian subsidiary of the company, was stopped from buying a stake in a Chennai-based company due to objections raised by the Ministry of Home Affairs (MHA). Etisalat DB was not allowed to buy back the 5.27 percent stake held by Chennai-based Genex Exim Ventures since the home ministry raised objections based largely on security concerns. The MHA had pointed out four issues that needed to be resolved before allowing the company to come into Etisalat DB, a company that got scarce 2G spectrum at allegedly throwaway prices.

It raised objections about Etisalat's presence in Pakistan and its connection with Pakistan's intelligence agency ISI. Etisalat owns a 26% stake in Pakistan Telecommunications and has a subscriber base of 3 million in Afghanistan. The MHA has also expressed concerns about the telecom surveillance software Etisalat had used in a Blackberry service it had introduced in the UAE and recommended that the company should not be allowed to offer Blackberry services in India.

On 22 February 2012, Etisalat announced that it will cease operations in India post-cancellation of its licenses by the Supreme Court of India. It issued notice to its subscribers, giving them 30 days to change operators. On 5 September 2012, Etisalat announced that it would not bid for spectrum in the November 2012 2G spectrum auction. In a released statement the company said, "Etisalat Group has decided not to participate in the auction as it is not willing to re-participate after being canceled its owned licenses. Following the publication by the Department of Telecomm (DoT) – India’s Ministry of Communications and Information Technology of the information memorandum for the planned auction of spectrum in 1800 MHz and 800 MHz bands, the Emirates Telecommunications Corporation (Etisalat) wishes to confirm that it has decided not to participate in the auction".

title: Etisalat by e&


text:
Rosh HaNikra

Rosh Hanikra (רֹאשׁ הַנִּקְרָה, lit. Head of the Grottoes) may refer to:

 * Rosh HaNikra grottoes, a geographic feature in Israel; article contains the main history section regarding the cape and the Ladder of Tyre
 * Rosh HaNikra (kibbutz), a kibbutz nearby
 * Rosh Hanikra cheese, a soft white cheese made in the area
 * Rosh HaNikra Crossing, a border crossing between Israel and Lebanon
 * Rosh HaNikra Islands, c. 800 m offshore from the cape with the grottoes

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

title: Rosh HaNikra


text:
Householder transformation

In linear algebra, a Householder transformation (also known as a Householder reflection or elementary reflector) is a linear transformation that describes a reflection about a plane or hyperplane containing the origin. The Householder transformation was used in a 1958 paper by Alston Scott Householder.

Its analogue over general inner product spaces is the Householder operator.

Transformation
The reflection hyperplane can be defined by its normal vector, a unit vector $v$ (a vector with length $1$ ) that is orthogonal to the hyperplane. The reflection of a point $x$ about this hyperplane is the linear transformation:

 * $$x - 2\langle x, v\rangle v = x - 2v\left(v^* x\right), $$

where $v$ is given as a column unit vector with conjugate transpose $v^\textsf{*}$.

Householder matrix
The matrix constructed from this transformation can be expressed in terms of an outer product as:

 * $$P = I - 2vv^*$$

is known as the Householder matrix, where $I$ is the identity matrix.

Properties
The Householder matrix has the following properties:
 * it is Hermitian: $P = P^*$ ,
 * it is unitary: $P^{-1} = P^*$ ,
 * hence it is involutory: $P = P^{-1}$.
 * A Householder matrix has eigenvalues $\pm 1$ . To see this, notice that if $u$  is orthogonal to the vector $v$  which was used to create the reflector, then $Pu = u$, i.e., $1$  is an eigenvalue of multiplicity $n - 1$ , since there are $n - 1$  independent vectors orthogonal to $v$ .  Also, notice $Pv = -v$ , and so $-1$  is an eigenvalue with multiplicity $1$.
 * The determinant of a Householder reflector is $-1$, since the determinant of a matrix is the product of its eigenvalues, in this case one of which is $-1$ with the remainder being $1$  (as in the previous point).

Geometric optics
In geometric optics, specular reflection can be expressed in terms of the Householder matrix (see ).

Numerical linear algebra
Householder transformations are widely used in numerical linear algebra, for example, to annihilate the entries below the main diagonal of a matrix, to perform QR decompositions and in the first step of the QR algorithm. They are also widely used for transforming to a Hessenberg form. For symmetric or Hermitian matrices, the symmetry can be preserved, resulting in tridiagonalization.

QR decomposition
Householder reflections can be used to calculate QR decompositions by reflecting first one column of a matrix onto a multiple of a standard basis vector, calculating the transformation matrix, multiplying it with the original matrix and then recursing down the $(i, i)$ minors of that product. To accomplish this, a hermitian unitary matrix Q is sought which takes a complex vector x into a complex multiple of a complex vector e. For the QR decomposition, e will be a unit coordinate vector, say for the kth coordinate. A complex matrix Q having the form Q = I - u u* with u* u = 2 has the desired property of being hermitian unitary. Here * denotes the conjugate transpose. Since the only two vectors involved are x and e, the vector u must have the form u = a x + b e, where a and b are complex coefficients to be determined. Since an overall phase factor for u does not matter, the coefficient a can be chosen to be positive real. Now Q x = x (1 – a (u* x)) - e (b (u* x)). For the coefficient of the vector x to be zero, the two terms in u* x must have the same phase within a multiple of 180 degrees, so we must have arg(b) = arg(e* x) within a multiple of 180 degrees. There are two solutions according to whether an even or odd multiple of 180 degrees is chosen. So for the complex coefficient of the vector x to be zero, two linear equations in the moduli of a and b must be solved. The phases of a and b have already been determined. Suppose e to be the kth unit coordinate vector so that e* e = 1 and xk= e* x and let |x|= sqrt(x* x). Then a and b may be expressed simply either as  a =1/sqrt (|x| (|x|+ |xk|)) and b = a |x| exp(i*arg(xk)) or as  a =1/sqrt (|x| (|x|- |xk|)) and b = - a |x| exp(i*arg(xk)). The multiplier of e is -b/a for both solutions. The first solution is better because the denominator cannot be near zero compared to |x|.

Tridiagonalization
This procedure is presented in Numerical Analysis by Burden and Faires. It uses a slightly altered $$\operatorname{sgn}$$ function with $$\operatorname{sgn}(0) = 1$$. In the first step, to form the Householder matrix in each step we need to determine $\alpha$ and $r$, which are:
 * $$\begin{align}

\alpha &= -\operatorname{sgn}\left(a_{21}\right)\sqrt{\sum_{j=2}^n a_{j1}^2}; \\ r &= \sqrt{\frac{1}{2}\left(\alpha^2 - a_{21}\alpha\right)}; \end{align}$$

From $\alpha$ and $r$, construct vector $v$ :

 * $$v^{(1)} = \begin{bmatrix} v_1 \\ v_2 \\ \vdots \\ v_n \end{bmatrix},$$

where $v_1 = 0$, $v_2 = \frac{a_{21} - \alpha}{2r}$ , and
 * $$v_k = \frac{a_{k1}}{2r}$$ for each $$k = 3, 4 \ldots n$$

Then compute:
 * $$\begin{align}

P^1 &= I - 2v^{(1)} \left(v^{(1)}\right)^\textsf{T} \\ A^{(2)} &= P^1 AP^1 \end{align}$$

Having found $P^1$ and computed $A^{(2)}$  the process is repeated for $k = 2, 3, \ldots, n - 2$  as follows:

 * $$\begin{align}

\alpha &= -\operatorname{sgn}\left(a^k_{k+1,k}\right)\sqrt{\sum_{j=k+1}^n \left(a^k_{jk}\right)^2} \\[2pt] r &= \sqrt{\frac{1}{2}\left(\alpha^2 - a^k_{k+1,k}\alpha\right)} \\[2pt] v^k_1 &= v^k_2 = \cdots = v^k_k = 0 \\[2pt] v^k_{k+1} &= \frac{a^k_{k+1,k} - \alpha}{2r} \\ v^k_j &= \frac{a^k_{jk}}{2r} \text{ for } j = k + 2,\ k + 3,\ \ldots,\ n \\ P^k &= I - 2v^{(k)} \left(v^{(k)}\right)^\textsf{T} \\ A^{(k+1)} &= P^k A^{(k)}P^k \end{align}$$

Continuing in this manner, the tridiagonal and symmetric matrix is formed.

Examples
In this example, also from Burden and Faires, the given matrix is transformed to the similar tridiagonal matrix A3 by using the Householder method.

 * $$\mathbf{A} = \begin{bmatrix}

4 & 1 & -2 & 2 \\   1 & 2 &  0 &  1 \\  -2 & 0 &  3 & -2 \\   2 & 1 & -2 & -1 \end{bmatrix},$$

Following those steps in the Householder method, we have:

The first Householder matrix:
 * $$\begin{align}

Q_1 &= \begin{bmatrix} 1 &          0 &           0  &           0  \\      0 & -\frac{1}{3} & \frac{2}{3} & -\frac{2}{3} \\ 0 & \frac{2}{3} & \frac{2}{3} &  \frac{1}{3} \\ 0 & -\frac{2}{3} & \frac{1}{3} & \frac{2}{3} \end{bmatrix}, \\ A_2 = Q_1 A Q_1 &= \begin{bmatrix} 4 & -3          &  0           &  0 \\      -3 & \frac{10}{3} &  1           &  \frac{4}{3} \\ 0 & 1           &  \frac{5}{3} & -\frac{4}{3} \\ 0 & \frac{4}{3} & -\frac{4}{3} & -1 \end{bmatrix}, \end{align}$$

Used $A_2$ to form
 * $$\begin{align}

Q_2 &= \begin{bmatrix} 1 & 0 & 0           &  0           \\    0 & 1 &  0           &  0           \\    0 & 0 & -\frac{3}{5} & -\frac{4}{5} \\ 0 & 0 & -\frac{4}{5} & \frac{3}{5} \end{bmatrix}, \\ A_3 = Q_2 A_2 Q_2 &= \begin{bmatrix} 4 & -3           &            0   &             0  \\    -3 &  \frac{10}{3} &  -\frac{5}{3}  &             0  \\ 0 & -\frac{5}{3} & -\frac{33}{25} &  \frac{68}{75} \\ 0 & 0            &  \frac{68}{75} & \frac{149}{75} \end{bmatrix}, \end{align}$$

As we can see, the final result is a tridiagonal symmetric matrix which is similar to the original one. The process is finished after two steps.

Computational and theoretical relationship to other unitary transformations
The Householder transformation is a reflection about a hyperplane with unit normal vector $v$, as stated earlier. An $N$ -by-$N$ unitary transformation $U$  satisfies $UU^* = I$. Taking the determinant ($N$ -th power of the geometric mean) and trace (proportional to arithmetic mean) of a unitary matrix reveals that its eigenvalues $\lambda_i$  have unit modulus. This can be seen directly and swiftly:
 * $$\begin{align}

\frac{\operatorname{Trace}\left(UU^*\right)}{N} &= \frac{\sum_{j=1}^N\left|\lambda_j\right|^2}{N} = 1, & \operatorname{det}\left(UU^*\right) &= \prod_{j=1}^N \left|\lambda_j\right|^2 = 1. \end{align}$$

Since arithmetic and geometric means are equal if the variables are constant (see inequality of arithmetic and geometric means), we establish the claim of unit modulus.

For the case of real valued unitary matrices we obtain orthogonal matrices, $UU^\textsf{T} = I$. It follows rather readily (see orthogonal matrix) that any orthogonal matrix can be decomposed into a product of 2 by 2 rotations, called Givens Rotations, and Householder reflections. This is appealing intuitively since multiplication of a vector by an orthogonal matrix preserves the length of that vector, and rotations and reflections exhaust the set of (real valued) geometric operations that render invariant a vector's length.

The Householder transformation was shown to have a one-to-one relationship with the canonical coset decomposition of unitary matrices defined in group theory, which can be used to parametrize unitary operators in a very efficient manner.

Finally we note that a single Householder transform, unlike a solitary Givens transform, can act on all columns of a matrix, and as such exhibits the lowest computational cost for QR decomposition and tridiagonalization. The penalty for this "computational optimality" is, of course, that Householder operations cannot be as deeply or efficiently parallelized. As such Householder is preferred for dense matrices on sequential machines, whilst Givens is preferred on sparse matrices, and/or parallel machines.

title: Householder transformation


text:
Advanced Boolean Expression Language

The Advanced Boolean Expression Language (ABEL) is an obsolete hardware description language (HDL) and an associated set of design tools for programming programmable logic devices (PLDs). It was created in 1983 by Data I/O Corporation, in Redmond, Washington.

ABEL includes both concurrent equation and truth table logic formats as well as a sequential state machine description format. A preprocessor with syntax loosely based on Digital Equipment Corporation's MACRO-11 assembly language is also included.

In addition to being used for describing digital logic, ABEL may also be used to describe test vectors (patterns of inputs and expected outputs) that may be downloaded to a hardware PLD programmer along with the compiled and fuse-mapped PLD programming data.

Other PLD design languages originating in the same era include CUPL and PALASM. Since the advent of larger field-programmable gate arrays (FPGAs), PLD-specific HDLs have fallen out of favor as standard HDLs such as Verilog and VHDL gained adoption.

The ABEL concept and original compiler were created by Russell de Pina of Data I/O's Applied Research Group in 1981. The work was continued by ABEL product development team (led by Dr. Kyu Y. Lee) and included Mary Bailey, Bjorn Benson, Walter Bright, Michael Holley, Charles Olivier, and David Pellerin.

After a series of acquisitions, the ABEL toolchain and intellectual property were bought by Xilinx. Xilinx discontinued support for ABEL in its ISE Design Suite starting with version 11 (released in 2010).

title: Advanced Boolean Expression Language


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User:Matt Borak/sandbox

confessions of zeno

http://www.sontongaquartet.com/confessions.html - first book with plot dealing with freudian psychoanalysis

Google fight Czechia vs Czech Republic and Česko vs Česká republika: 25/04/05 - 420 000 : 44 500 000 = 0.9438 and

04.08.2000 - ROMAN KRASNICKÝ - str. 01 Czechia, Czechlands, Czech? - jen ne Čečna

P r a h a - Česká republika má v zahraničí potíže s vlastním jménem, tedy hlavně s jeho zkrácenou verzí. Doma pomalu vítězí Česko, ale v cizině, kde dominuje angličtina, převládají rozpaky. Na první pohled se zdá, že získává navrch Czechia. Toto slovo například používali britský ministr zahraničí Robin Cook nebo Jos Chabert, prezident Výboru regionů Evropské unie, při svých návštěvách Prahy minulý měsíc. A stejné označení zavedla například i CNN ve svém internetovém zpravodajství. Avšak nedávný skandál na Světové výstavě EXPO 2000 v Hannoveru, kdy organizátoři v anglické verzi oficiálního plánku výstaviště označili český pavilon jako čečenský, ukazuje, že slovo Czechia se ještě nevžilo. "Tato aféra je důsledkem naší nechuti jasně světu sdělit, jak se vlastně jmenujeme. Vedení pavilonu používá pouze název The Czech Republic. Jak tedy měli němečtí organizátoři vědět, že existuje Czechia," říká Leoš Jeleček z katedry sociální geografie Univerzity Karlovy. Podle jeho názoru je v angličtině jasno už od roku 1993, kdy názvoslovná komise při Českém úřadě geodetickém a kartografickém vybrala pro potřeby OSN označení Česko a v angličtině Czechia. Úředníci a politici však stále váhají. Ilustruje to i postoj resortu školství. V listopadu 1999 sice ministr Eduard Zeman ve věstníku ministerstva doporučil školám vhodným způsobem propagovat slovo Česko i jeho anglický ekvivalent Czechia, ale v červnu tohoto roku náměstek Ladislav Malý v dopise Jelečkovi podpořil stanovisko hokejového svazu, který nadále bude chápat slovo Czech jako zkrácení oficiálního názvu Czech Republic. Pod tímto označením budou tedy čeští hokejisté vyjíždět na led k dalším mezistátním zápasům. "Použití názvu Czechia se svazu nejeví jako nejvhodnější, což je i náš názor," píše Malý. "Stačilo by, kdyby na konferencích naši politici a diplomaté před sebe položili na stůl tabulku s Czechia, a během krátké doby se tento název v zahraničí vžije," tvrdí Jeleček. Podle jazykovědce Jiřího Felixe z Univerzity Karlovy je trapné, když naši představitelé v zahraničí vystupují zásadně pod hlavičkou Czech Republic. "Nikdo nás přece za království nepovažuje. Tím, že používáme dvouslovný název, jakoby demonstrujeme své republikánství," říká Felix. Někteří lidé pohybující se v anglicky mluvícím prostředí však o vhodnosti slova Czechia pochybují. "Svou výslovností až příliš připomíná Chechnya, tedy Čečensko, lepší by možná bylo používat The Czechlands," domnívá se Dagmar Gillespie, vedoucí londýnské pobočky České centrály cestovního ruchu. Velvyslanec České republiky ve Velké Británii Pavel Seifter zastává podobný názor: "Slovo Czechia je naprosto nešťastné. Nedá se číst jinak než jako Čečnia. Zkoušel jsem propagovat The Czechlands, jak to před lety navrhoval Saša Vondra, ale na to je už asi pozdě. Pro označení České republiky se však v poslední době ujímá mezi Brity přídavné jméno Czech, což je pro mě šokující," říká. Záměna Česka s Čečenskem není jen "anglický" problém. Roku 1997 si tehdejší kancléř Helmut Kohl v Bundestagu během projevu o německé zahraniční politice popletl Česko a Čečensko. Tschechien a Tschetschenien zní velmi podobně. Ve stanovisku ministerstva zahraničí z února 1993, které reagovalo na dotazy zahraničních diplomatů a novinářů, jak se vlastně Česko jmenuje, se preferoval název The Czechlands. O pět let později však tehdejší náměstek ministra zahraničí Jan Winkler zaslal všem českým zastupitelským úřadům materiál, v němž se doporučuje používat Czechia. "Mám-li si vybrat mezi Czechia a The Czechlands, kloním se k tomu druhému. Ale chápu, že to s sebou přináší také problémy," říká český velvyslanec v USA Saša Vondra.

title: User:Matt Borak/sandbox


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Chinese martial arts

Chinese martial arts, commonly referred to with umbrella terms kung fu, kuoshu or wushu , are multiple fighting styles that have developed over the centuries in Greater China. These fighting styles are often classified according to common traits, identified as "families" of martial arts. Examples of such traits include Shaolinquan  physical exercises involving All Other Animals  mimicry or training methods inspired by Old Chinese philosophies, religions and legends. Styles that focus on qi manipulation are called internal (内家拳; ), while others that concentrate on improving muscle and cardiovascular fitness are called external (外家拳; ). Geographical associations, as in northern (北拳; ) and southern (南拳; ), is another popular classification method.

Terminology
Kung fu and wushu are loanwords from Cantonese and Mandarin respectively that, in English, are used to refer to Chinese martial arts. However, the Chinese terms kung fu and wushu have distinct meanings. The Chinese equivalent of the term "Chinese martial arts" would be Zhongguo wushu (Mandarin).

In Chinese, the term kung fu refers to any skill that is acquired through learning or practice. It is a compound word composed of the words 功 (gōng) meaning "work", "achievement", or "merit", and 夫 (fū) which is a particle or nominal suffix with diverse meanings.

Wushu literally means "martial art". It is formed from the two Chinese characters 武術: 武 (wǔ), meaning "martial" or "military" and 術 or 术 (shù), which translates into "art", "discipline", "skill" or "method". The term wushu has also become the name for the modern sport of wushu, an exhibition and full-contact sport of bare-handed and weapon forms, adapted and judged to a set of aesthetic criteria for points developed since 1949 in the People's Republic of China.

Quánfǎ (拳法) is another Chinese term for Chinese martial arts. It means "fist method" or "the law of the fist" (quán means "boxing" or "fist", and fǎ means "law", "way" or "method"), although as a compound term it usually translates as "boxing" or "fighting technique." The name of the Japanese martial art kempō is represented by the same hanzi characters.

History
The genesis of Chinese martial arts has been attributed to the need for self-defense, hunting techniques and military training in ancient China. Hand-to-hand combat and weapons practice were important in training ancient Chinese soldiers.

Detailed knowledge about the state and development of Chinese martial arts became available from the Nanjing decade (1928–1937), as the Central Guoshu Institute established by the Kuomintang regime made an effort to compile an encyclopedic survey of martial arts schools. Since the 1950s, the People's Republic of China has organized Chinese martial arts as an exhibition and full-contact sport under the heading of "wushu".

Legendary origins
According to legend, Chinese martial arts originated before the semi-mythical Xia dynasty over 4,000 years ago. It is said that the Yellow Emperor (Huangdi), who ascended to power in 2698 BCE, introduced the earliest fighting systems to China. The Emperor is renowned as a great general who, prior to becoming China's leader, authored extensive treatises on medicine, astrology, and the martial arts. One of his primary adversaries was Chi You, credited as the progenitor of jiao di, a precursor to modern Chinese wrestling.

Early history
The earliest references to Chinese martial arts are found in the Spring and Autumn Annals (5th century BCE), where a hand-to-hand combat theory, one that integrates notions of "hard" and "soft" techniques, is mentioned. A combat wrestling system called juélì or jiǎolì (角力) is mentioned in the Classic of Rites. This combat system included techniques such as strikes, throws, joint manipulation, and pressure point attacks. Jiao Di became a sport during the Qin dynasty (221–207 BCE). The Han History Bibliographies record that, by the Former Han (206 BCE – 8 CE), there was a distinction between no-holds-barred weaponless fighting, which it calls shǒubó (手搏), for which training manuals had already been written, and sportive wrestling, then known as juélì (角力). Wrestling is also documented in the Shǐ Jì, Records of the Grand Historian, written by Sima Qian (ca. 100 BCE).

In the Tang dynasty, descriptions of sword dances were immortalized in poems by Li Bai. In the Song and Yuan dynasties, xiangpu(相扑) contests were sponsored by the imperial courts. The modern concepts of wushu were fully developed by the Ming and Qing dynasties.

Philosophical influences
The ideas associated with Chinese martial arts changed with the evolution of Chinese society and over time acquired some philosophical bases: Passages in the Zhuangzi (莊子), a Taoist text, pertain to the psychology and practice of martial arts. Zhuangzi, its eponymous author, is believed to have lived in the 4th century BCE. The Tao Te Ching, often credited to Laozi, is another Taoist text that contains principles applicable to martial arts. According to one of the classic texts of Confucianism, Zhou Li (周禮), Archery and charioteering were part of the "six arts" (, including rites, music, calligraphy and mathematics) of the Zhou dynasty (1122–256 BCE). The Art of War, written during the 6th century BCE by Sun Tzu , deals directly with military warfare but contains ideas that are used in the Chinese martial arts.

Taoist practitioners have been practicing daoyin (physical exercises similar to qigong that was one of the progenitors to tai chi) from as early as 500 BCE. In 39–92 CE, "Six Chapters of Hand Fighting", were included in the Han Shu (history of the Former Han dynasty) written by Ban Gu. Also, the noted physician, Hua Tuo, composed the "Five Animals Play"—tiger, deer, monkey, bear, and bird, around 208 CE. Taoist philosophy and their approach to health and exercise have influenced the Chinese martial arts to a certain extent. Direct reference to Taoist concepts can be found in such styles as the "Eight Immortals," which uses fighting techniques attributed to the characteristics of each immortal.

Shaolin temple established
In 495 CE, the first Shaolin temple was constructed on Song Mountain in Henan province. The initial Buddhist monk who propagated Buddhism there was an Indian monk named Buddhabhadra, known as Batuo in Chinese. Historical records suggest that Batuo's first Chinese disciples, Huiguang and Sengchou, possessed exceptional martial skills. For instance, Sengchou's proficiency with the tin staff is documented in the Chinese Buddhist canon. Following Buddhabhadra, another Indian monk named Bodhidharma, also known as Damo in Chinese, arrived at Shaolin in 527 CE. His Chinese disciple, Huike, was likewise a highly skilled martial artist. There are indications that these first three Chinese Shaolin monks—Huiguang, Sengchou, and Huike—may have had a military background prior to embracing monastic life.

Shaolin and temple-based martial arts

The Shaolin style of kung fu is considered one of the earliest organized Chinese martial arts. The oldest documented evidence of Shaolin's involvement in combat dates back to a stele from 728 CE, which records two significant events: the defense of the Shaolin Monastery against bandits around 610 CE and their subsequent contribution to the defeat of Wang Shichong at the Battle of Hulao in 621 CE. However, between the 8th and 15th centuries, there are no surviving records that provide concrete proof of Shaolin's involvement in combat activities.

Between the 16th and 17th centuries, at least forty sources exist to provide evidence both that monks of Shaolin practiced martial arts, and that martial practice became an integral element of Shaolin monastic life. The earliest appearance of the frequently cited legend concerning Bodhidharma's supposed foundation of Shaolin kung fu dates to this period. The origin of this legend has been traced to the Ming period's Yijin Jing or "Muscle Change Classic", a text written in 1624 attributed to Bodhidharma.

References of martial arts practice in Shaolin appear in various literary genres of the late Ming: the epitaphs of Shaolin warrior monks, martial-arts manuals, military encyclopedias, historical writings, travelogues, fiction, and poetry. However, these sources do not point out any specific style that originated in Shaolin. These sources, in contrast to those from the Tang period, refer to Shaolin methods of armed combat. These include a skill for which Shaolin monks became famous: the staff (gùn, Cantonese gwan). The Ming general Qi Jiguang included a description of Shaolin kung fu and staff techniques in his book, Jixiao Xinshu, which can translate as New Book Recording Effective Techniques. When this book spread across East Asia, it had a great influence on the development of martial arts in regions such as Okinawa and Korea.

Republican period
Most fighting styles that are being practiced as traditional Chinese martial arts today reached their popularity within the 20th century. Some of these include Baguazhang, Drunken Boxing, Eagle Claw, Five Animals, Xingyi, Hung Gar, Monkey, Bak Mei Pai, Northern Praying Mantis, Southern Praying Mantis, Fujian White Crane, Jow Ga, Wing Chun and tai chi. The increase in the popularity of those styles is a result of the dramatic changes occurring within the Chinese society.

In 1900–01, the Righteous and Harmonious Fists rose against foreign occupiers and Christian missionaries in China. This uprising is known in the West as the Boxer Rebellion due to the martial arts and calisthenics practiced by the rebels. Empress Dowager Cixi gained control of the rebellion and tried to use it against the foreign powers. The failure of the rebellion led ten years later to the fall of the Qing dynasty and the creation of the Chinese Republic.

The present view of Chinese martial arts is strongly influenced by the events of the Republican period (1912–1949). In the transition period between the fall of the Qing dynasty as well as the turmoil of the Japanese invasion and the Chinese Civil War, Chinese martial arts became more accessible to the general public as many martial artists were encouraged to openly teach their art. At that time, some considered martial arts as a means to promote national pride and build a strong nation. As a result, many training manuals (拳譜) were published, a training academy was created, two national examinations were organized and demonstration teams traveled overseas. Numerous martial arts associations were formed throughout China and in various overseas Chinese communities. The Central Guoshu Academy (Zhongyang Guoshuguan, 中央國術館) established by the National Government in 1928 and the Jing Wu Athletic Association (精武體育會) founded by Huo Yuanjia in 1910 are examples of organizations that promoted a systematic approach for training in Chinese martial arts. A series of provincial and national competitions were organized by the Republican government starting in 1932 to promote Chinese martial arts. In 1936, at the 11th Olympic Games in Berlin, a group of Chinese martial artists demonstrated their art to an international audience for the first time.

The term kuoshu (or guoshu, 國術 meaning "national art"), rather than the colloquial term gongfu was introduced by the Kuomintang in an effort to more closely associate Chinese martial arts with national pride rather than individual accomplishment.

People's Republic
Chinese martial arts experienced rapid international dissemination with the end of the Chinese Civil War and the founding of the People's Republic of China on October 1, 1949. Many well known martial artists chose to escape from the PRC's rule and migrate to Taiwan, Hong Kong, and other parts of the world. Those masters started to teach within the overseas Chinese communities but eventually they expanded their teachings to include people from other ethnic groups. Within China, the practice of traditional martial arts was discouraged during the turbulent years of the Chinese Cultural Revolution (1969–1976). Like many other aspects of traditional Chinese life, martial arts were subjected to a radical transformation by the People's Republic of China to align them with Maoist revolutionary doctrine. The PRC promoted the committee-regulated sport of Wushu as a replacement for independent schools of martial arts. This new competition sport was disassociated from what was seen as the potentially subversive self-defense aspects and family lineages of Chinese martial arts.

In 1958, the government established the All-China Wushu Association as an umbrella organization to regulate martial arts training. The Chinese State Commission for Physical Culture and Sports took the lead in creating standardized forms for most of the major arts. During this period, a national Wushu system that included standard forms, teaching curriculum, and instructor grading was established. Wushu was introduced at both the high school and university level. The suppression of traditional teaching was relaxed during the Era of Reconstruction (1976–1989), as Communist ideology became more accommodating to alternative viewpoints. In 1979, the State Commission for Physical Culture and Sports created a special task force to reevaluate the teaching and practice of Wushu. In 1986, the Chinese National Research Institute of Wushu was established as the central authority for the research and administration of Wushu activities in the People's Republic of China.

Changing government policies and attitudes towards sports, in general, led to the closing of the State Sports Commission (the central sports authority) in 1998. This closure is viewed as an attempt to partially de-politicize organized sports and move Chinese sport policies towards a more market-driven approach. As a result of these changing sociological factors within China, both traditional styles and modern Wushu approaches are being promoted by the Chinese government.

Chinese martial arts are an integral element of 20th-century Chinese popular culture. Wuxia or "martial arts fiction" is a popular genre that emerged in the early 20th century and peaked in popularity during the 1960s to 1980s. Wuxia films were produced from the 1920s. The Kuomintang suppressed wuxia, accusing it of promoting superstition and violent anarchy. Because of this, wuxia came to flourish in British Hong Kong, and the genre of kung fu movie in Hong Kong action cinema became wildly popular, coming to international attention from the 1970s. The genre underwent a drastic decline in the late 1990s as the Hong Kong film industry was crushed by economic depression.

In the wake of Ang Lee's Crouching Tiger, Hidden Dragon (2000), there has been somewhat of a revival of Chinese-produced wuxia films aimed at an international audience, including Zhang Yimou's Hero (2002), House of Flying Daggers (2004) and Curse of the Golden Flower (2006), as well as Su Chao-pin and John Woo's Reign of Assassins (2010).

Styles
China boasts a rich history of martial arts traditions encompassing numerous styles, totaling in the hundreds. Over the course of the past two millennia, a multitude of distinct styles have been developed, each with its own unique techniques and philosophies. These styles are often categorized into "families" (家; jiā), "schools" (派; pai), or "sects" (門; men). While each style possesses its own characteristics, there are also common themes that thread through different styles.

Some styles draw inspiration from animal movements, replicating the agility and power of creatures such as tigers, snakes, or monkeys. Others derive their inspiration from Chinese philosophies, myths, and legends, incorporating their principles and symbolism into their techniques. Certain styles place significant emphasis on harnessing and manipulating qi, while others prioritize competitive aspects, focusing on sparring and tournaments.

The diversity of Chinese martial arts reflects the vast array of cultural and regional influences throughout history. From the graceful and flowing movements of Tai Chi to the explosive and acrobatic techniques of Wushu, China's martial arts traditions showcase a vibrant tapestry of physical prowess, philosophical principles, and cultural heritage.

Chinese martial arts can be split into various categories to differentiate them: For example, "external" (外家拳) and "internal" (內家拳). Chinese martial arts can also be categorized by location, as in "northern" and "southern" as well, referring to what part of China the styles originated from, separated by the Yangtze River; Chinese martial arts may even be classified according to their province or city. The main perceived difference between northern and southern styles is that the northern styles tend to emphasize fast and powerful kicks, high jumps and generally fluid and rapid movement, while the southern styles focus more on strong arm and hand techniques, and stable, immovable stances and fast footwork. Examples of the northern styles include changquan and xingyiquan. Examples of the southern styles include Bak Mei, Wuzuquan, Choy Li Fut, and Wing Chun. Chinese martial arts can also be divided according to religion, imitative-styles (象形拳), and family styles such as Hung Gar (洪家). There are distinctive differences in the training between different groups of the Chinese martial arts regardless of the type of classification. However, few experienced martial artists make a clear distinction between internal and external styles, or subscribe to the idea of northern systems being predominantly kick-based and southern systems relying more heavily on upper-body techniques. Most styles contain both hard and soft elements, regardless of their internal nomenclature. Analyzing the difference in accordance with yin and yang principles, philosophers would assert that the absence of either one would render the practitioner's skills unbalanced or deficient, as yin and yang alone are each only half of a whole. If such differences did once exist, they have since been blurred.

Training
Chinese martial arts training consists of the following components: basics, forms, applications and weapons; different styles place varying emphasis on each component. In addition, philosophy, ethics and even medical practice are highly regarded by most Chinese martial arts. A complete training system should also provide insight into Chinese attitudes and culture.

Moreover, many Chinese martial arts styles integrate traditional medical practices into their training. This includes the understanding of meridians, pressure points, and herbal remedies, as well as exercises that promote health, vitality, and longevity. The holistic approach to training seeks to cultivate both internal and external strength, promoting overall well-being and balance.

Furthermore, Chinese martial arts serve as a vessel for preserving and transmitting cultural values and attitudes. Respect for teachers, dedication, discipline, and perseverance are instilled in practitioners, fostering a sense of community and loyalty within martial arts schools and lineages. Chinese martial arts also often incorporate cultural elements such as music, costumes, and rituals, further deepening the connection to Chinese heritage and traditions.

Overall, Chinese martial arts encompass not just physical techniques but a comprehensive system that encompasses philosophy, ethics, medical knowledge, and cultural appreciation. It is this holistic approach that distinguishes Chinese martial arts as not just a means of self-defense but as a way of life, promoting personal growth, cultural understanding, and the pursuit of harmony and excellence.

Basics
The Basics (基本功) are a vital part of any martial training, as a student cannot progress to the more advanced stages without them. Basics are usually made up of rudimentary techniques, conditioning exercises, including stances. Basic training may involve simple movements that are performed repeatedly; other examples of basic training are stretching, meditation, striking, throwing, or jumping. Without strong and flexible muscles, management of qi or breath, and proper body mechanics, it is impossible for a student to progress in the Chinese martial arts. A common saying concerning basic training in Chinese martial arts is as follows: "内外相合，外重手眼身法步，内修心神意氣力."

Which translates as:

"Train both Internal and External. External training includes the hands, the eyes, the body and stances. Internal training includes the heart, the spirit, the mind, breathing and strength."

Stances
Stances (steps or 步法) are structural postures employed in Chinese martial arts training. They represent the foundation and the form of a fighter's base. Each style has different names and variations for each stance. Stances may be differentiated by foot position, weight distribution, body alignment, etc. Stance training can be practiced statically, the goal of which is to maintain the structure of the stance through a set time period, or dynamically, in which case a series of movements is performed repeatedly. The Horse stance (騎馬步/馬步; ) and the bow stance are examples of stances found in many styles of Chinese martial arts.

Meditation
In many Chinese martial arts, meditation is considered to be an important component of basic training. Meditation can be used to develop focus, mental clarity and can act as a basis for qigong training. Through meditation, martial arts practitioners learn to regulate their breath, relax their bodies, and enter a state of deep focus. This kind of concentration helps them to stay present in their movements and techniques, enhancing their responsiveness and physical coordination. Meditation also cultivates the ability for introspection, enabling practitioners to become more keenly aware of their bodily sensations, energy flow, and inner state. Meditation is also closely related to qigong. Through the concentration and adjustments achieved through meditation, martial arts practitioners can better perceive and direct the internal energy (known as "qi" in qigong). They learn to manipulate the flow of qi through deep breathing and visualization exercises to promote bodily balance, harmony, and health. Therefore, meditation, as a part of foundational training, offers Chinese martial arts practitioners a comprehensive approach to cultivating both the internal and external aspects. It assists them in developing various aspects of their body, energy, and mind, thereby enhancing their technical skills.

Use of qi
The concept of qi is encountered in a number of Chinese martial arts. Qi is variously defined as an inner energy or "life force" that is said to animate living beings; as a term for proper skeletal alignment and efficient use of musculature (sometimes also known as fa jin or jin); or as a shorthand for concepts that the martial arts student might not yet be ready to understand in full. These meanings are not necessarily mutually exclusive. The existence of qi as a measurable form of energy as discussed in traditional Chinese medicine has no basis in the scientific understanding of physics, medicine, biology or human physiology.

There are many ideas regarding the control of one's qi energy to such an extent that it can be used for healing oneself or others. Some styles believe in focusing qi into a single point when attacking and aim at specific areas of the human body. Such techniques are known as dim mak and have principles that are similar to acupressure.

Weapons training
Most Chinese styles also make use of training in the broad arsenal of Chinese weapons for conditioning the body as well as coordination and strategy drills. Weapons training (器械; ) is generally carried out after the student becomes proficient with the basic forms and applications training. The basic theory for weapons training is to consider the weapon as an extension of the body. It has the same requirements for footwork and body coordination as the basics. The process of weapon training proceeds with forms, forms with partners and then applications. Most systems have training methods for each of the Eighteen Arms of Wushu(十八般兵器; ) in addition to specialized instruments specific to the system.

Application
Application refers to the practical use of combative techniques. Chinese martial arts techniques are ideally based on efficiency and effectiveness. Application includes non-compliant drills, such as Pushing Hands in many internal martial arts, and sparring, which occurs within a variety of contact levels and rule sets.

When and how applications are taught varies from style to style. Today, many styles begin to teach new students by focusing on exercises in which each student knows a prescribed range of combat and technique to drill on. These drills are often semi-compliant, meaning one student does not offer active resistance to a technique, in order to allow its demonstrative, clean execution. In more resisting drills, fewer rules apply, and students practice how to react and respond. 'Sparring' refers to a more advanced format, which simulates a combat situation while including rules that reduce the chance of serious injury.

Competitive sparring disciplines include Chinese kickboxing Sǎnshǒu (散手) and Chinese folk wrestling Shuāijiāo (摔跤), which were traditionally contested on a raised platform arena, or Lèitái (擂台). Lèitái were used in public challenge matches first appeared in the Song dynasty. The objective for those contests was to knock the opponent from a raised platform by any means necessary. San Shou represents the modern development of Lei Tai contests, but with rules in place to reduce the chance of serious injury. Many Chinese martial art schools teach or work within the rule sets of Sanshou, working to incorporate the movements, characteristics, and theory of their style. Chinese martial artists also compete in non-Chinese or mixed Combat sport, including boxing, kickboxing and Mixed martial arts.

Forms (taolu)
Forms or taolu in Chinese are series of predetermined movements combined so they can be practiced as a continuous set of movements. Forms were originally intended to preserve the lineage of a particular style branch, and were often taught to advanced students selected for that purpose. Forms contained both literal, representative and exercise-oriented forms of applicable techniques that students could extract, test, and train in through sparring sessions.

Today, many consider taolu to be one of the most important practices in Chinese martial arts. Traditionally, they played a smaller role in training for combat application and took a back seat to sparring, drilling, and conditioning. Forms gradually build up a practitioner's flexibility, internal and external strength, speed and stamina, and they teach balance and coordination. Many styles contain forms that use weapons of various lengths and types, using one or two hands. Some styles focus on a certain type of weapon. Forms are meant to be both practical, usable, and applicable as well as to promote fluid motion, meditation, flexibility, balance, and coordination. Students are encouraged to visualize an attacker while training the form.

There are two general types of taolu in Chinese martial arts. Most common are solo forms performed by a single student. There are also sparring forms — choreographed fighting sets performed by two or more people. Sparring forms were designed both to acquaint beginning fighters with basic measures and concepts of combat and to serve as performance pieces for the school. Weapons-based sparring forms are especially useful for teaching students the extension, range, and technique required to manage a weapon.

Forms in traditional Chinese martial arts
The term taolu (套路) is a shortened version of Tao Lu Yun Dong (套路運動), an expression introduced only recently with the popularity of modern wushu. This expression refers to "exercise sets" and used in the context of athletics or sport.

In contrast, in traditional Chinese martial arts alternative terminologies for the training (練) of 'sets or forms are:

 * lian quan tao (練拳套) – practicing a sequence of fists.
 * lian quan jiao (練拳腳) – practicing fists and feet.
 * lian bing qi (練兵器) – practicing weapons.
 * dui da (對打) and dui lian (對練) – fighting sets.

Traditional "sparring" sets, called dui da (對打) or dui lian (對練), were an essential part of Chinese martial arts for centuries. Dui lian means to train by a pair of combatants opposing each other—the character lian (練), refers to practice; to train; to perfect one's skill; to drill. As well, often one of these terms are also included in the name of fighting sets (雙演; shuang yan), "paired practice" (掙勝; zheng sheng), "to struggle with strength for victory" (敵; di), match – the character suggests to strike an enemy; and "to break" (破; po).

Generally, there are 21, 18, 12, 9 or 5 drills or 'exchanges/groupings' of attacks and counterattacks, in each dui lian set. These drills were considered only generic patterns and never meant to be considered inflexible 'tricks'. Students practiced smaller parts/exchanges, individually with opponents switching sides in a continuous flow. Dui lian were not only sophisticated and effective methods of passing on the fighting knowledge of the older generation, but they were also essential and effective training methods. The relationship between single sets and contact sets is complicated, in that some skills cannot be developed with solo 'sets', and, conversely, with dui lian. Unfortunately, it appears that most traditional combat oriented dui lian and their training methodology have disappeared, especially those concerning weapons. There are several reasons for this. In modern Chinese martial arts, most of the dui lian are recent inventions designed for light props resembling weapons, with safety and drama in mind. The role of this kind of training has degenerated to the point of being useless in a practical sense, and, at best, is just performance.

By the early Song period, sets were not so much "individual isolated technique strung together" but rather were composed of techniques and counter technique groupings. It is quite clear that "sets" and "fighting (two-person) sets" have been instrumental in traditional Chinese martial arts for many hundreds of years—even before the Song dynasty. There are images of two-person weapon training in Chinese stone painting going back at least to the Eastern Han dynasty.

According to what has been passed on by the older generations, the approximate ratio of contact sets to single sets was approximately 1:3. In other words, about 30% of the 'sets' practiced at Shaolin were contact sets, dui lian, and two-person drill training. This ratio is, in part, evidenced by the Qing dynasty mural at Shaolin.

For most of its history, Shaolin martial arts was mostly weapon-focused: staves were used to defend the monastery, not bare hands. Even the more recent military exploits of Shaolin during the Ming and Qing dynasties involved weapons. According to some traditions, monks first studied basics for one year and were then taught staff fighting so that they could protect the monastery. Although wrestling has been a sport in China for centuries, weapons have been an essential part of Chinese wushu since ancient times. If one wants to talk about recent or 'modern' developments in Chinese martial arts (including Shaolin for that matter), it is the over-emphasis on bare hand fighting. During the Northern Song dynasty (976–997 A.D.) when platform fighting is known as Da Laitai (Title Fights Challenge on Platform) first appeared, these fights were with only swords and staves. Although later, when bare hand fights appeared as well, it was the weapons events that became the most famous. These open-ring competitions had regulations and were organized by government organizations; the public also organized some. The government competitions, held in the capital and prefectures, resulted in appointments for winners, to military posts.

Practice forms vs. kung fu in combat
Even though forms in Chinese martial arts are intended to depict realistic martial techniques, the movements are not always identical to how techniques would be applied in combat. Many forms have been elaborated upon, on the one hand, to provide better combat preparedness, and on the other hand to look more aesthetically pleasing. One manifestation of this tendency toward elaboration beyond combat application is the use of lower stances and higher, stretching kicks. These two maneuvers are unrealistic in combat and are used in forms for exercise purposes. Many modern schools have replaced practical defense or offense movements with acrobatic feats that are more spectacular to watch, thereby gaining favor during exhibitions and competitions. This has led to criticisms by traditionalists of the endorsement of the more acrobatic, show-oriented Wushu competition. Historically forms were often performed for entertainment purposes long before the advent of modern Wushu as practitioners have looked for supplementary income by performing on the streets or in theaters. Documentation in ancient literature during the Tang dynasty (618–907) and the Northern Song dynasty (960–1279) suggests some sets, (including two + person sets: dui da also called dui lian) became very elaborate and 'flowery', many mainly concerned with aesthetics. During this time, some martial arts systems devolved to the point that they became popular forms of martial art storytelling entertainment shows. This created an entire category of martial arts known as Hua Fa Wuyi. During the Northern Song period, it was noted by historians this type of training had a negative influence on training in the military.

Many traditional Chinese martial artists, as well as practitioners of modern sport combat, have become critical of the perception that forms work is more relevant to the art than sparring and drill application, while most continue to see traditional forms practice within the traditional context—as vital to both proper combat execution, the Shaolin aesthetic as an art form, as well as upholding the meditative function of the physical art form.

Another reason why techniques often appear different in forms when contrasted with sparring application is thought by some to come from the concealment of the actual functions of the techniques from outsiders.

Forms practice is mostly known for teaching combat techniques yet when practicing forms, the practitioner focuses on posture, breathing, and performing the techniques of both right and left sides of the body.

Wushu

The word wu (武; ) means "martial". Its Chinese character is made of two parts; the first meaning "walk" or "stop" (止; ') and the second meaning "lance" (戈; '). This implies that "wu 武" is a defensive use of combat. The term "wushu 武術" meaning "martial arts" goes back as far as the Liang dynasty (502–557) in an anthology compiled by Xiao Tong (蕭通), (Prince Zhaoming; 昭明太子 d. 531), called Selected Literature (文選; ). The term is found in the second verse of a poem by Yan Yanzhi titled: 皇太子釋奠會作詩 "Huang Taizi Shidian Hui Zuoshi".

The great man grows the many myriad things ... Breaking away from the military arts, He promotes fully the cultural mandates.

— Translated from Echoes of the Past by Yan Yanzhi (384–456)

The term wushu is also found in a poem by Cheng Shao (1626–1644) from the Ming dynasty.

The earliest term for 'martial arts' can be found in the Han History (206 BC – 23 AD) was "military fighting techniques" (兵技巧; ). During the Song period (c.960) the name changed to "martial arts" (武藝; ). In 1928 the name was changed to "national arts" (國術; ) when the National Martial Arts Academy was established in Nanjing. The term reverted to wǔshù under the People's Republic of China during the early 1950s.

As forms have grown in complexity and quantity over the years, and many forms alone could be practiced for a lifetime, modern styles of Chinese martial arts have developed that concentrate solely on forms, and do not practice application at all. These styles are primarily aimed at exhibition and competition, and often include more acrobatic jumps and movements added for enhanced visual effect compared to the traditional styles. Those who generally prefer to practice traditional styles, focused less on exhibition, are often referred to as traditionalists. Some traditionalists consider the competition forms of today's Chinese martial arts as too commercialized and losing much of their original values.

"Martial morality"
Traditional Chinese schools of martial arts, such as the famed Shaolin monks, often dealt with the study of martial arts not just as a means of self-defense or mental training, but as a system of ethics. Wude (武 德) can be translated as "martial morality" and is constructed from the words wu (武), which means martial, and de (德), which means morality. Wude deals with two aspects; "Virtue of deed" and "Virtue of mind". Virtue of deed concerns social relations; morality of mind is meant to cultivate the inner harmony between the emotional mind (心; ) and the wisdom mind (慧; ). The ultimate goal is reaching "no extremity" (無 極; ) – closely related to the Taoist concept of wu wei – where both wisdom and emotions are in harmony with each other.

Virtues:

Notable practitioners
Examples of well-known practitioners (武術名師) throughout history:

 * Yue Fei (1103–1142 CE) was a famous Chinese general and patriot of the Song dynasty. Styles such as Eagle Claw and Xingyiquan attribute their creation to Yue. However, there is no historical evidence to support the claim he created these styles.
 * Ng Mui (late 17th century) was the legendary female founder of many Southern martial arts such as Wing Chun, and Fujian White Crane. She is often considered one of the legendary Five Elders who survived the destruction of the Shaolin Temple during the Qing dynasty.
 * Yang Luchan (1799–1872) was an important teacher of the internal martial art known as tai chi in Beijing during the second half of the 19th century. Yang is known as the founder of Yang-style tai chi, as well as transmitting the art to the Wu/Hao, Wu and Sun tai chi families.
 * Ten Tigers of Canton (late 19th century) was a group of ten of the top Chinese martial arts masters in Guangdong (Canton) towards the end of the Qing dynasty (1644–1912). Wong Kei-Ying, Wong Fei Hung's father, was a member of this group.
 * Wong Fei Hung (1847–1924) was considered a Chinese folk hero during the Republican period. More than one hundred Hong Kong movies were made about his life. Sammo Hung, Jackie Chan, and Jet Li have all portrayed his character in blockbuster pictures.
 * Huo Yuanjia (1867–1910) was the founder of Chin Woo Athletic Association who was known for his highly publicized matches with foreigners. His biography was recently portrayed in the movie Fearless (2006).
 * Ip Man (1893–1972) was a master of the Wing Chun and the first to teach this style openly. Yip Man was the teacher of Bruce Lee. Most major branches of Wing Chun taught in the West today were developed and promoted by students of Yip Man.
 * Gu Ruzhang (1894–1952) was a Chinese martial artist who disseminated the Bak Siu Lum (Northern Shaolin) martial arts system across southern China in the early 20th century. Gu was known for his expertise in Iron Palm hand conditioning among other Chinese martial art training exercises.
 * Bruce Lee (1940–1973) was a Chinese-American martial artist and actor who was considered an important icon in the 20th century. He practiced Wing Chun and made it famous. Using Wing Chun as his base and learning from the influences of other martial arts his experience exposed him to, he later developed his own martial arts philosophy that evolved into what is now called Jeet Kune Do.
 * Jackie Chan (b. 1954) is the famous Hong Kong martial artist, film actor, stuntman, action choreographer, director and producer, and a global pop culture icon, widely known for injecting physical comedy into his martial arts performances, and for performing complex stunts in many of his films.
 * Jet Li (b. 1963) is the five-time sport wushu champion of China, later demonstrating his skills in cinema.
 * Donnie Yen (b. 1963) is a Hong Kong actor, martial artist, film director and producer, action choreographer, and world wushu tournament medalist.
 * Wu Jing (b. 1974) is a Chinese actor, director, and martial artist. He was a member of the Beijing wushu team, and started his career as action choreographer and later as an actor.

In popular culture
References to the concepts and use of Chinese martial arts can be found in popular culture. Historically, the influence of Chinese martial arts can be found in books and in the performance arts specific to Asia. Recently, those influences have extended to the movies and television that targets a much wider audience. As a result, Chinese martial arts have spread beyond its ethnic roots and have a global appeal.

Martial arts play a prominent role in the literature genre known as wuxia (武俠小說). This type of fiction is based on Chinese concepts of chivalry, a separate martial arts society (武林; ) and a central theme involving martial arts. Wuxia stories can be traced as far back as 2nd and 3rd century BCE, becoming popular by the Tang dynasty and evolving into novel form by the Ming dynasty. This genre is still extremely popular in much of Asia and provides a major influence for the public perception of the martial arts.

Martial arts influences can also be found in dance, theater and especially Chinese opera, of which Beijing opera is one of the best-known examples. This popular form of drama dates back to the Tang dynasty and continues to be an example of Chinese culture. Some martial arts movements can be found in Chinese opera and some martial artists can be found as performers in Chinese operas.

In modern times, Chinese martial arts have spawned the genre of cinema known as the Kung fu film. The films of Bruce Lee were instrumental in the initial burst of Chinese martial arts' popularity in the West in the 1970s. Bruce Lee was the iconic international superstar that popularized Chinese martial arts in the West with his own variation of Chinese martial arts called Jeet Kune Do. It is a hybrid style of martial art that Bruce Lee practiced and mastered. Jeet Kune Do is his very own unique style of martial art that uses little to minimum movement but maximizes the effect to his opponents. The influence of Chinese martial art have been widely recognized and have a global appeal in Western cinemas starting off with Bruce Lee.

Martial artists and actors such as Jet Li and Jackie Chan have continued the appeal of movies of this genre. Jackie Chan successfully brought in a sense of humour in his fighting style in his movies. Martial arts films from China are often referred to as "kung fu movies" (功夫片), or "wire-fu" if extensive wire work is performed for special effects, and are still best known as part of the tradition of kung fu theater. (see also: wuxia, Hong Kong action cinema). The talent of these individuals have broadened Hong Kong's cinematography production and rose to popularity overseas, influencing Western cinemas.

In the west, kung fu has become a regular action staple, and makes appearances in many films that would not generally be considered "Martial Arts" films. These films include but are not limited to The Matrix franchise, Kill Bill, and The Transporter.

Martial arts themes can also be found on television networks. A U.S. network TV western series of the early 1970s called Kung Fu also served to popularize the Chinese martial arts on television. With 60 episodes over a three-year span, it was one of the first North American TV shows that tried to convey the philosophy and practice in Chinese martial arts. The use of Chinese martial arts techniques can now be found in most TV action series, although the philosophy of Chinese martial arts is seldom portrayed in depth. In the 2006 music video of Knights of Cydonia by Muse, the protagonist can be seen training Chinese martial arts in the opening. In 2022, martial arts and action sequences inspired by Hong Kong cinema can be found in Everything Everywhere All at Once.

The Kung Fu Diaries: The Life and Times of a Dragon Master (1920–2001) is a work of fiction, combining aspects of biography, historical fiction, and guide to instruction purportedly from a collection of diaries or papers left by a Kung-Fu Dragon Master.

Influence on hip hop
In the 1970s, Bruce Lee was beginning to gain popularity in Hollywood for his martial arts movies. The fact that he was a non-white male who portrayed self-reliance and righteous self-discipline resonated with black audiences and made him an important figure in this community. Around 1973, Kung Fu movies became a hit in America across all backgrounds; however, black audiences maintained the films' popularity well after the general public lost interest. Black youth in New York City were still going from every borough to Times Square every night to watch the latest movies. Amongst these individuals were those coming from the Bronx where, during this time, hip-hop was beginning to take form. One of the pioneers responsible for the development of the foundational aspects of hip-hop was DJ Kool Herc, who began creating this new form of music by taking rhythmic breakdowns of songs and looping them. From the new music came a new form of dance known as b-boying or breakdancing, a style of street dance consisting of improvised acrobatic moves. The pioneers of this dance credit kung fu as one of its influences. Moves such as the crouching low leg sweep and "up rocking" (standing combat moves) are influenced by choreographed kung-fu fights. The dancers' ability to improvise these moves led way to battles, which were dance competitions between two dancers or crews judged on their creativity, skills, and musicality. In a documentary, Crazy Legs, a member of breakdancing group Rock Steady Crew described the breakdancing battle being like an old kung fu movie, "where the one kung fu master says something along the lines of 'hun your kung fu is good, but mine is better,' then a fight erupts."

title: Chinese martial arts


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Suicide by cop

Suicide by cop (abbreviated as: SbC ), also known as suicide by police or law-enforcement-assisted suicide, is a suicide method in which a suicidal individual deliberately behaves in a threatening manner with intent to provoke a lethal response from a public safety or law enforcement officer to end their own life.

Overview
There are two broad categories of "suicide by cop". The first is when someone has committed a crime and is being pursued by the police and decides that they would rather die than be arrested. These people may not otherwise be suicidal but may simply decide that life is not worth living if they are incarcerated and thus will provoke police to kill them. The second version involves people who are already contemplating suicide and who decide to provoke law enforcement into killing them. These individuals may commit a crime with the specific intention of provoking a law enforcement response.

The idea of dying by suicide in this manner is based on trained procedures of law enforcement officers, specifically the policy on the use of deadly force. In jurisdictions where officials are readily capable of deadly force, often by being equipped with firearms, there are usually set circumstances where they will predictably use deadly force against a threat to themselves or others. This form of suicide functions by exploiting this trained reaction. The most common scenario is pointing a firearm at a police officer or an innocent person, which would be expected to provoke an officer to fire on them. Many variants exist: for example, attacking with a knife or other hand weapon, trying to run an officer or other person over with a car, or trying to trigger a real or presumed explosive device.

This concept hinges on the person's state of mind, and their desire to end their own life, which can be difficult to determine post-mortem. Some cases are obvious, such as pointing an unloaded or non-functioning gun, such as a toy gun, air gun, airsoft gun, or starter's pistol, at officers, or the presence of a suicide note. Some suspects brazenly announce their intention to die before they act; however, many cases can be more difficult to determine, as some suspects with the desire to die will actually fire live ammunition and even kill people before being killed themselves. Many law enforcement training programs have added sections to specifically address handling these situations if officers suspect that the subject is attempting to goad them into using lethal force.

History
Many modern cases that pre-date the formal recognition of the phenomenon have been identified or speculated by historians as matching the pattern now known as suicide by cop. According to authors Mark Lindsay and David Lester, Houston McCoy, one of the two Austin Police Department officers who shot and killed Charles Whitman, the "Texas Tower Sniper", believed that Whitman could have shot him and fellow officer Ramiro Martinez, but "he was waiting for them, and wanted to be shot." The 1976 death of Mal Evans, road manager, assistant, and a friend of the Beatles, who aimed an air gun at police and refused to put it down, was theorized as a possible example of this phenomenon. Some historians believe that Giuseppe Zangara, the man who killed Chicago mayor Anton Cermak in a possible attempt to assassinate then President-elect Franklin D. Roosevelt, might have been attempting suicide by police.

Recognition and research
The phenomenon has been described in news accounts from 1981, and scientific journals since 1985. The phrase has appeared in news headlines since at least 1987. It did not become common until the early 2000s. The phrase seems to have originated in the United States, but has also appeared in the UK, where a jury first determined someone died by suicide by cop in 2003.

Some of the first research into suicide by cop was completed by Sgt. Rick Parent of the Delta Police Department in 2004. Parent's research of 843 police shootings determined that about 50% were victim-precipitated homicide. Police defined victim-precipitated homicide as "an incident in which an individual bent on self-destruction, engages in life threatening and criminal behavior to force law enforcement officers to kill them."

The first formally labeled "Suicide by Cop" case in English legal history was a judgment made on May 9, 2003, by the Reverend Dr. William Dolman while serving as a London coroner between 1993 and 2007. It set a legal precedent and the judgment, as a cause of death, has been a part of English law since.

A 2009 study in the United States of the profiles of 268 people who died by suicide by cop found that
 * 95% were male and 5% were female
 * the mean age was 35 for men
 * 41% of men were Caucasian, 26% Hispanic and 16% African American
 * 37% of men were single
 * 29% of men had children
 * 54% of men were unemployed
 * 29% of men did not have housing
 * 62% of men had confirmed or probable histories of mental health issues
 * 80% of men were armed – of these, 60% possessed firearms (of which 86% were loaded) and 26% possessed knives
 * 19% feigned or simulated weapon possession
 * 87% of individuals made suicidal communications prior to and/or during the incident
 * 36% were under the influence of alcohol.

A study of five years (2010-2015) of LAPD data on 419 attempted suicides by cop found that officers used lethal force seven times, killing five of the subjects. Less-lethal force was used 71 times. No force was used the other 341 times, or 81 percent. LAPD’s Mental Evaluation Unit has specially trained officers to handle such incidents and tracked, paired with mental health clinicians, who are on call 24 hours a day.

In the US, the Police Executive Research Forum developed a protocol for dealing with incidents, in which officers do not aim their weapon at the person, move a safe distance away and engage the person in conversation rather than shouting commands at them.

Examples

 * According to the Beatles researcher Kenneth Womack, the death of band's roadie Mal Evans in 1976 was a suicide by cop, as Evans had written a will the night before.
 * In the Aramoana massacre, a spree shooting that occurred on 13 November 1990 in New Zealand, police shot the suspect dead as he came out of a house firing from the hip and screaming "Kill me!"
 * On 5 May 2005, Peggy Jo Tallas, a bank robber, engaged in a shootout while armed with a toy pistol.
 * In December 2008, 15-year-old Tyler Cassidy was shot and killed by three Victoria Police officers after he threatened them with two large knives and ordered them to shoot him.
 * During March 2011, Chilean businessman and organized criminal Italo Nolli was shot and killed by police after shooting dead two investigative police detectives and hurting another five. He had previously stated to his wife and son that he believed dying in a police shootout would be "dignifying" and that he "would not return to prison".
 * Myron May, a 31-year-old man believing he was a victim of government covert electronic harassment on the line of Cold War era MKUltra and COINTELPRO clandestine US government programs, died by suicide by cop on 20 November 2014 after recording his intentions on tape.
 * On 4 January 2015, a 32-year-old San Francisco man, Matthew Hoffman, staged a standoff with police in the parking lot of an SFPD station. When he brandished the gun, two officers shot him a total of three times. He left a message for the officers on his cell phone, saying: "You did nothing wrong. You ended the life of a man who was too much of a coward to do it himself ... I provoked you. I threatened your life as well as the lives of those around me."
 * In June 2015, 21-year-old Trepierre Hummons, a known gangster with a history of weapons violations, posted his intent to die by suicide by cop on Facebook on the same day that a sex offense had been reported against him. He called 9-1-1 and reported he had seen a man acting erratically with a gun. He then shot the responding officer multiple times, mortally wounding him. The next officer to arrive on the scene shot Hummons. Both Hummons and the wounded policeman later died in the hospital.
 * On 22 October 2015, Anton Lundin Pettersson, the perpetrator of the Trollhättan school stabbing, wrote a message to an online friend an hour before the attack, where he states “I hope those fucking cops aim straight, because I really don't want to survive my rampage.". He also wrote that he expected to be dead within one or two hours and that he hated himself. Pettersson had a history of mental illness, and a book about the attack with interviews of many people around him states that "during the period before the attack, he wavered between several options; to seek professional help, to kill himself 'normally' or to attack people around him to get killed."
 * On 28 May 2017, a man in Mississippi suspected of murdering seven of his family members and a police officer told a journalist that by shooting towards police, "Suicide by cop was my intention. I ain't fit to live. Not after what I've done."
 * On 15 September 2017, a 15-year-old Virginia boy, Ruben Urbina, called police and was shot twice after threatening an officer with a crowbar. After calling 911, he made threats of a bomb, hostages, knives and guns, none of which were real. "I called the police… so they can kill me."
 * On August 30, 2018, American actress Vanessa Marquez pleaded with police officers to kill her while pointing a replica gun at them. Officers were unaware the gun was a replica, and they shot her to death in self-defense.
 * In 2018, Alek Minassian, the perpetrator of the Toronto van attack, claimed to have attempted suicide by cop when apprehended by police after his attack, requesting to be killed and claiming he was armed with a gun, a declaration which was false.

In literary fiction
In To Kill a Mockingbird, Tom Robinson, a despondent black man who is imprisoned for a rape he did not commit, is shot 17 times and killed while trying to escape from prison in front of the prison guards.

In The Outsiders, Dallas Winston, a juvenile delinquent, aims an unloaded handgun at police officers with the intent of them shooting him; he is shot dead.

title: Suicide by cop