Emil Leon Post
In his Columbia University doctoral thesis, he proved, among other things, that the propositional calculus of Principia Mathematica was complete: all tautologies are theorems, given the Principia axioms and a rule of uniform substitution. Van Heijenoort's (1966) source book on mathematical logic reprinted Post's classic article setting out this result. This thesis also devised truth tables independently of Wittgenstein and Charles Peirce and put them to good mathematical use.
- E. L. Post, "Recursively enumerable sets of positive integers and their decision problems", Bulletin of the American Mathematical Society 50 (1944) 284-316
In this article Post introduced the important concept of many-one reduction.
- Davis, Martin (1993). The Undecidable (Ed.), pp. 288-406. Dover. ISBN 0-486-43228-9. Reprints several papers by Post.
- Davis, Martin (1994). "Emil L. Post: His Life and Work" in Davis, M., ed., Solvability, Provability, Definability: The Collected Works of Emil L. Post. Birkhäuser: xi--xxviii. A biographical essay.
- O'Connor, John J., and Edmund F. Robertson. "Emil Leon Post". MacTutor History of Mathematics archive.