262 Logic as a Tool of any Turing machine and an input for it and determine as an output whether that Turing machine will eventually halt for that input Turing then concluded that Hilbert’s Entscheidungsproblem has no solution, thus reproving this fundamental result which had recently been published by Church Turing completed a doctorate in mathematical logic in Princeton University under Church’s supervision in 1938 Church and Turing showed that the Church’s lambda calculus and the Turing machine were equivalent as models of computation, and argued that they capture precisely the intuitive notion of algorithm; this claim became known as the Church–Turing thesis In 1938, Turing was invited to work for the British crypto-analytic department to help break the secret codes of the German encrypting machines Enigma Turing was instrumental in developing methods and constructing special devices, called Bombe, for decrypting messages sent by Enigma coders, saving many lives during the course of the World War II At the end of the war Turing was invited by the National Physical Laboratory in London to design a real, physical computer and he submitted a report proposing the Automatic Computing Engine (ACE) in 1946 Turing was a homosexual and was arrested and convicted for violation of the British anti-homosexuality law in 1952 To avoid going to prison, he agreed to chemical castration Turing died in 1954 of cyanide poisoning, widely believed to be suicide following his prosecution and treatment In 2009 the British Prime Minister offered an official apology from the British Government for Turing’s prosecution, and in 2013 he was granted a royal pardon by the Queen In 1966 the Association for Computing Machinery established the Turing Award as the most prestigious award for scientific contributions in computer science, regarded as the equivalent to the Nobel Prize