Logical framework

Source: Wikipedia, the free encyclopedia.

In

Isabelle are based on this idea.[1] Unlike a direct embedding, the logical framework approach allows many logics to be embedded in the same type system.[3]

Overview

A logical framework is based on a general treatment of syntax, rules and proofs by means of a

dependently typed lambda calculus. Syntax is treated in a style similar to, but more general than Per Martin-Löf
's system of arities.

To describe a logical framework, one must provide the following:

  1. A characterization of the class of object-logics to be represented;
  2. An appropriate meta-language;
  3. A characterization of the mechanism by which object-logics are represented.

This is summarized by:

"Framework = Language + Representation."

LF

In the case of the LF logical framework, the meta-language is the

Church-Rosser and the property of being well-typed is decidable. However, type inference
is undecidable.

A logic is represented in the LF logical framework by the judgements-as-types representation mechanism. This is inspired by

judgement
, in the 1983 Siena Lectures. The two higher-order judgements, the hypothetical and the general, , correspond to the ordinary and dependent function space, respectively. The methodology of judgements-as-types is that judgements are represented as the types of their proofs. A
logical system
is represented by its signature which assigns kinds and types to a finite set of constants that represents its syntax, its judgements and its rule schemes. An object-logic's rules and proofs are seen as primitive proofs of hypothetico-general judgements .

An implementation of the LF logical framework is provided by the Twelf system at Carnegie Mellon University. Twelf includes

  • a logic programming engine
  • meta-theoretic reasoning about logic programs (termination, coverage, etc.)
  • an inductive
    meta-logical
    theorem prover

See also

References

  1. ^
    ISBN 978-0-444-50853-9
    .
  2. ISBN 978-0-19-853859-2
    .
  3. ISBN 978-3-642-03152-6
    .

Further reading

  • ISBN 978-1-4020-0608-1
    .
  • Robert Harper, Furio Honsell and Gordon Plotkin. A Framework For Defining Logics. Journal of the Association for Computing Machinery, 40(1):143-184, 1993.
  • Arnon Avron, Furio Honsell, Ian Mason and Randy Pollack. Using typed lambda calculus to implement formal systems on a machine. Journal of Automated Reasoning, 9:309-354, 1992.
  • Robert Harper. An Equational Formulation of LF. Technical Report, University of Edinburgh, 1988. LFCS report ECS-LFCS-88-67.
  • Robert Harper, Donald Sannella and Andrzej Tarlecki. Structured Theory Presentations and Logic Representations. Annals of Pure and Applied Logic, 67(1-3):113-160, 1994.
  • Samin Ishtiaq and David Pym. A Relevant Analysis of Natural Deduction. Journal of Logic and Computation 8, 809-838, 1998.
  • Samin Ishtiaq and David Pym. Kripke Resource Models of a Dependently-typed, Bunched -calculus. Journal of Logic and Computation 12(6), 1061-1104, 2002.
  • Per Martin-Löf. "On the Meanings of the Logical Constants and the Justifications of the Logical Laws." "Nordic Journal of Philosophical Logic", 1(1): 11-60, 1996.
  • Bengt Nordström, Kent Petersson, and Jan M. Smith. Programming in Martin-Löf's Type Theory. Oxford University Press, 1990. (The book is out of print, but a free version has been made available.)
  • David Pym. A Note on the Proof Theory of the -calculus. Studia Logica 54: 199-230, 1995.
  • David Pym and Lincoln Wallen. Proof-search in the -calculus. In: G. Huet and G. Plotkin (eds), Logical Frameworks, Cambridge University Press, 1991.
  • Didier Galmiche and David Pym. Proof-search in type-theoretic languages:an introduction. Theoretical Computer Science 232 (2000) 5-53.
  • Philippa Gardner. Representing Logics in Type Theory. Technical Report, University of Edinburgh, 1992. LFCS report ECS-LFCS-92-227.
  • Gilles Dowek. The undecidability of typability in the lambda-pi-calculus. In M. Bezem, J.F. Groote (Eds.), Typed Lambda Calculi and Applications. Volume 664 of Lecture Notes in Computer Science, 139-145, 1993.
  • David Pym. Proofs, Search and Computation in General Logic. Ph.D. thesis, University of Edinburgh, 1990.
  • David Pym. A Unification Algorithm for the -calculus. International Journal of Foundations of Computer Science 3(3), 333-378, 1992.

External links

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