Alonzo Church
Alonzo Church (born June 14, 1903 in Washington, DC , † August 11, 1995 in Hudson , Ohio ) was an American mathematician , logician and philosopher and one of the founders of theoretical computer science .
Career
Church studied at Princeton University , where he graduated in mathematics with a doctorate in 1927. After stays at the University of Chicago , the Georg August University of Göttingen and the University of Amsterdam, he became Professor of Mathematics at Princeton in 1929. Church remained a professor at Princeton for nearly four decades until 1967. He then moved to the University of California, Los Angeles (UCLA), where he was professor of mathematics and philosophy until 1990.
His doctoral students include a. C. Anthony Anderson , Peter B. Andrews , George A. Barnard , David Berlinski , William W. Boone , Martin Davis , Alfred L. Foster , Leon Henkin , John G. Kemeny , Stephen C. Kleene , Simon B. Cooking , Maurice L'Abbé , Isaac Malitz , Gary R. Mar , Michael O. Rabin , Nicholas Rescher , Hartley Rogers, Jr. , J. Barkley Rosser , Dana Scott , Raymond Smullyan , and Alan Turing .
plant
He became known to his mathematical and logical colleagues in the 1930s with a universal formal model for calculations, the lambda calculus , which he developed as part of his research on the fundamentals of mathematics and Gödel's incompleteness theorems . Data and operators are embedded in the lambda calculus using Church coding , natural numbers are represented by Church numerals . Church demonstrated in 1936 that there is no computable function for two given expressions in the lambda calculus to decide whether they are equivalent or not, i.e. problems undecidable by number theorem (Church theorem); two equivalent expressions are to be converted into one another or reduced to the same normal form ( Church-Rosser theorem ). This prompted his student Alan Turing to think about the problem of holding a machine performing arithmetic operations. Church and Turing then found that the lambda calculus and the Turing machine are equal models in terms of the decision problem ; a concept of predictability derived from this is known as the Church-Turing thesis .
In the field of philosophy, he is known for his high level of argumentation, defended Platonic position in the modern universal controversy.
Fonts
- Introduction to Mathematical Logic ( ISBN 978-0-691-02906-1 )
- The Calculi of Lambda-Conversion ( ISBN 978-0-691-08394-0 )
- A Bibliography of Symbolic Logic, 1666-1935 ( ISBN 978-0-8218-0084-3 )
literature
- C. Anthony Anderson, Michael Zelëny (Eds.): Logic, Meaning and Computation: Essays in Memory of Alonzo Church , Synthesis Library, Vol. 305, 2002, ISBN 978-1-4020-0141-3
Web links
- John J. O'Connor, Edmund F. Robertson : Alonzo Church. In: MacTutor History of Mathematics archive .
Individual evidence
- ^ Mathematics Genealogy Project . Archived from the original on August 4, 2010. Retrieved on August 12, 2010.
- ↑ Alonzo Church, "An Unsolvable Problem of Elementary Number Theory," American Journal of Mathematics, Volume 58, No. 2, April 1936, pp. 345-363.
- ^ Joseph Maria Bocheński , Alonso Church, Nelson Goodman : The Problem of Universals. A Symposium , Notre Dame, Ind., 1956, 33-57
| personal data | |
|---|---|
| SURNAME | Church, Alonzo |
| BRIEF DESCRIPTION | American mathematician and one of the founders of theoretical computer science |
| DATE OF BIRTH | June 14, 1903 |
| PLACE OF BIRTH | Washington, DC |
| DATE OF DEATH | August 11, 1995 |
| Place of death | Hudson (Ohio) |