# Alan Turing

**TuringAlan M. TuringAlan Mathison TuringChristopher MorcomTuring, AlanAlan TurningAllan TuringJulius Mathison TuringTuring, ATuring, A.**

Alan Mathison Turing (23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher and theoretical biologist.wikipedia

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### Turing machine

**deterministic Turing machineTuring machinesuniversal computer**

Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer.

The Turing machine was invented in 1936 by Alan Turing, who called it an "a-machine" (automatic machine).

### Bletchley Park

**Bletchley Park MuseumBletchley Park TrustBletchley**

During the Second World War, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain's codebreaking centre that produced Ultra intelligence.

During World War II, the estate housed the British Government Code and Cypher School (GC&CS), which regularly penetrated the secret communications of the Axis Powers – most importantly the German Enigma and Lorenz ciphers; among its most notable early personnel the GC&CS team of codebreakers included Alan Turing, Gordon Welchman, Hugh Alexander and Stuart Milner-Barry.

### Artificial intelligence

**AIA.I.artificially intelligent**

Turing is widely considered to be the father of theoretical computer science and artificial intelligence.

The study of mathematical logic led directly to Alan Turing's theory of computation, which suggested that a machine, by shuffling symbols as simple as "0" and "1", could simulate any conceivable act of mathematical deduction.

### Algorithm

**algorithmsalgorithm designcomputer algorithm**

Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer.

Those formalizations included the Gödel–Herbrand–Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's Formulation 1 of 1936, and Alan Turing's Turing machines of 1936–37 and 1939.

### Computer

**computerscomputer systemdigital computer**

Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer.

The principle of the modern computer was proposed by Alan Turing in his seminal 1936 paper, On Computable Numbers.

### Hut 8

**Turing's section**

For a time he led Hut 8, the section that was responsible for German naval cryptanalysis.

The section was led initially by Alan Turing.

### Ultra

**Ultra secret ULTRA Special Liaison Unit**

During the Second World War, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain's codebreaking centre that produced Ultra intelligence.

At Bletchley Park, some of the key people responsible for success against Enigma included mathematicians Alan Turing and Hugh Alexander and, at the British Tabulating Machine Company, chief engineer Harold Keen.

### Alan Turing law

**Sexual Offences (Pardons) billTuring's Law**

The Alan Turing law is now an informal term for a 2017 law in the United Kingdom that retroactively pardoned men cautioned or convicted under historical legislation that outlawed homosexual acts.

The provision is named after Alan Turing, the World War II codebreaker and computing pioneer, who was convicted of gross indecency in 1952.

### Labouchere Amendment

**gross indecencygross indecency" between malesLabouchère Amendment**

Turing was prosecuted in 1952 for homosexual acts; the Labouchere Amendment of 1885 had mandated that "gross indecency" was a criminal offence in the UK.

Most famously, Oscar Wilde was convicted under section 11 and sentenced to two years' hard labour, and Alan Turing was convicted under it and sentenced to oestrogen injections (chemical castration) as an alternative to prison.

### Halting problem

**always terminatesavoid the halting problemdetect non-terminating computations**

He went on to prove that there was no solution to the decision problem by first showing that the halting problem for Turing machines is undecidable: It is not possible to decide algorithmically whether a Turing machine will ever halt.

Alan Turing proved in 1936 that a general algorithm to solve the halting problem for all possible program-input pairs cannot exist.

### Turing's proof

**On Computable Numbers, with an Application to the EntscheidungsproblemOn Computable NumbersTuring's first and second proofs**

In 1936, Turing published his paper "On Computable Numbers, with an Application to the Entscheidungsproblem".

Turing's proof is a proof by Alan Turing, first published in January 1937 with the title "On Computable Numbers, with an Application to the Entscheidungsproblem."

### Maida Vale

**Little VeniceMaida HillMaida Vale Studios**

Turing was born in Maida Vale, London, while his father, Julius Mathison Turing (1873–1947), was on leave from his position with the Indian Civil Service (ICS) at Chatrapur, then in the Madras Presidency and presently in Odisha state, in India. However, both Julius and Ethel wanted their children to be brought up in Britain, so they moved to Maida Vale, London, where Alan Turing was born on 23 June 1912, as recorded by a blue plaque on the outside of the house of his birth, later the Colonnade Hotel.

The pioneer of modern computing, Alan Turing, was born at what is now the Colonnade Hotel in Warrington Crescent.

### Bank of England £50 note

**£50 note£50£50 notes**

In July 2019, the Bank of England announced that Turing would be depicted on the United Kingdom's new £50 note.

It will bear the image of Queen Elizabeth II on the obverse and the image of computer scientist World War II codebreaker Alan Turing on the reverse.

### Morphogenesis

**developmentmorphogeneticmorphogenic**

He wrote a paper on the chemical basis of morphogenesis and predicted oscillating chemical reactions such as the Belousov–Zhabotinsky reaction, first observed in the 1960s.

Some of the earliest ideas and mathematical descriptions on how physical processes and constraints affect biological growth, and hence natural patterns such as the spirals of phyllotaxis, were written by D'Arcy Wentworth Thompson in his 1917 book On Growth and Form and Alan Turing in his The Chemical Basis of Morphogenesis (1952).

### Princeton University Department of Mathematics

**Professor of MathematicsDepartment of MathematicsEugene Higgins Professor of Mathematics**

In June 1938, he obtained his PhD from the Department of Mathematics at Princeton; his dissertation, Systems of Logic Based on Ordinals, introduced the concept of ordinal logic and the notion of relative computing, where Turing machines are augmented with so-called oracles, allowing the study of problems that cannot be solved by Turing machines.

Notable individuals affiliated with the department include John Nash, Senior Research Mathematician and winner of the 1994 Nobel Prize; Alan Turing, who received his doctorates from the department; and Albert Einstein who frequently gave lectures at Princeton and had an office in the building.

### Universal Turing machine

**universaluniversal machineuniversality**

It also included a notion of a 'Universal Machine' (now known as a universal Turing machine), with the idea that such a machine could perform the tasks of any other computation machine (as indeed could Church's lambda calculus).

Alan Turing introduced the idea of such a machine in 1936–1937.

### Andrew Hodges

**Hodges, Andrew**

However, both The Churchill Centre and Turing's biographer Andrew Hodges have said they know of no documentary evidence to support this claim nor of the date or context in which Churchill supposedly said it, and the Churchill Centre lists it among their Churchill 'Myths', see and A BBC News profile piece that repeated the Churchill claim has subsequently been amended to say there is no evidence for it.

Hodges is best known as the author of Alan Turing: The Enigma, the story of the British computer pioneer and codebreaker Alan Turing.

### Church–Turing thesis

**Church-Turing thesisChurch's thesisTuring's Thesis**

According to the Church–Turing thesis, Turing machines and the lambda calculus are capable of computing anything that is computable.

The thesis is named after American mathematician Alonzo Church and the British mathematician Alan Turing.

### Banburismus

**Banbury sheets**

The others were: deducing the indicator procedure used by the German navy; developing a statistical procedure for making much more efficient use of the bombes dubbed Banburismus; developing a procedure for working out the cam settings of the wheels of the Lorenz SZ 40/42 (Tunny) dubbed Turingery and, towards the end of the war, the development of a portable secure voice scrambler at Hanslope Park that was codenamed Delilah.

Banburismus was a cryptanalytic process developed by Alan Turing at Bletchley Park in Britain during the Second World War.

### I. J. Good

**Jack GoodI.J. GoodGood, I. J.**

According to historian Ronald Lewin, Jack Good, a cryptanalyst who worked with Turing, said of his colleague:

was a British mathematician who worked as a cryptologist at Bletchley Park with Alan Turing.

### Max Newman

**M. H. A. NewmanMaxwell Herman Alexander NewmanNewman, Max**

In 1948, Turing joined Max Newman's Computing Machine Laboratory at the Victoria University of Manchester, where he helped develop the Manchester computers and became interested in mathematical biology.

He was appointed a lecturer in mathematics at Cambridge in 1927, where his 1935 lectures on the Foundations of Mathematics and Gödel's theorem inspired Alan Turing to embark on his pioneering work on the Entscheidungsproblem (decision problem) using a hypothetical computing machine.

### Colonnade Hotel

**Colonnade Hotel, London**

However, both Julius and Ethel wanted their children to be brought up in Britain, so they moved to Maida Vale, London, where Alan Turing was born on 23 June 1912, as recorded by a blue plaque on the outside of the house of his birth, later the Colonnade Hotel.

The mathematician Alan Turing was born there in 1912.

### Entscheidungsproblem

**Church's theoremcorrectly evaluate every statementDecision Problem**

The Entscheidungsproblem (decision problem) was originally posed by German mathematician David Hilbert in 1928.

In 1936, Alonzo Church and Alan Turing published independent papers showing that a general solution to the Entscheidungsproblem is impossible, assuming that the intuitive notion of "effectively calculable" is captured by the functions computable by a Turing machine (or equivalently, by those expressible in the lambda calculus).

### Chemical castration

**medical castrationchemically castratedchemical**

He accepted chemical castration treatment, with DES, as an alternative to prison.

In the United Kingdom, computer scientist Alan Turing, famous for his contributions to mathematics and computer science, pleaded guilty in 1952 to a charge of gross indecency for having a homosexual relationship and accepted chemical castration as a term of his probation, thus avoiding imprisonment.

### Turingery

**Turing's MethodTuringismus**

The others were: deducing the indicator procedure used by the German navy; developing a statistical procedure for making much more efficient use of the bombes dubbed Banburismus; developing a procedure for working out the cam settings of the wheels of the Lorenz SZ 40/42 (Tunny) dubbed Turingery and, towards the end of the war, the development of a portable secure voice scrambler at Hanslope Park that was codenamed Delilah.

Turingery or Turing's Method (playfully dubbed Turingismus by Peter Ericsson, Peter Hilton and Donald Michie ) was a hand codebreaking method devised in July 1942 by the mathematician and cryptanalyst Alan Turing at the British Government Code and Cypher School at Bletchley Park during World War II.