LISA@XX.LCS.MIT.EDU (Lisa F. Melcher) (09/26/86)
Date: Thursday, October 2, 1986 Time: 1:45 p.m......Refreshments Time: 2:00 p.m......Lecture Place: NE43 - 512A " GENERAL LOGIC " Gordon Plotkin Department of Computer Science University of Edinburgh, Scotland A good many logics have been proposed for use in Computer Science. Implementing them involves repeating a great deal of work. We propose a general account of logics as regards both their syntax and inference rules. As immediate target we envision a system to which one inputs a logic obtaining a simple proof-checker. The ideas build on work in logic of Paulson, Martin-Lof and Schroeder-Heister and in the typed lambda-calculus of Huet and Coquand and Meyer and Reinhold. The slogan is: Judgements are Types. For example the judgement that a proposition is true is identified with its type of proofs; general and hypothetical judgements are identified with dependent product types. This gives one account of Natural Deduction. It would be interesting to extend the work to consider (two-sided) sequent calculi for classical and modal logics. Sponsored by TOC, Laboratory for Computer Science Albert Meyer, Host -------
MESEGUER@CSL.SRI.COM (Jose Meseguer) (01/14/87)
GENERAL LOGIC by Prof. Gordon Plotkin C.S. Dept. Univ. of Edinburgh, Scotland WHEN: Thursday Jan. 15, at 1:30 pm WHERE: SRI, Room AA298 A wide variety of logics have been proposed for use in Computer Science , such as first-order , higher-order , type theories , temporal and modal logics , dynamic logic etc etc . One would like to write proof-checkers and (semi-) automatic theorem provers for them , but implementing any one is a major undertaking and it is very hard to vary the logic once work is underway . We propose a general syntactic theory of logic building on work of Martin-Lof and employing a lambda calculus of dependent types.It enables one to use a signature to enter the syntax and rules , in natural deuction style. It seems likely to allow the efficient production of basic proof checkers from the signature and to provide the user the tools to write theorem provers. -------