Computability logic
Introduced by Giorgi Japaridze in 2003, computability logic is a research programme and mathematical framework for redeveloping logic as a systematic formal theory of computability, as opposed to classical logic which is a formal theory of proof. In this approach logical formulas represent computational problems (or, equivalently, computational resources), and their validity means being "always computable".
Computational problems and resources are understood in their most general - interactive sense. They are formalized as games played by a machine against its environment, and computability means existence of a machine that wins the game against any possible behavior by the environment. Defining what such game-playing machines mean, computability logic provides a generalization of the Church-Turing thesis to the interactive level.
The classical concept of truth turns out to be[citation needed] a special, zero-interactivity-degree case of computability. This makes classical logic a special fragment of computability logic. Being a conservative extension of the former, computability logic is, at the same time, by an order of magnitude more expressive, constructive and computationally meaningful. Providing a systematic answer to the fundamental question "what (and how) can be computed?", it has a wide range of potential application areas. Those include constructive applied theories, knowledge base systems, systems for planning and action.
Besides classical logic, linear logic (understood in a relaxed sense) and intuitionistic logic also turn out to be natural fragments of computability logic. Hence meaningful concepts of "intuitionistic truth" and "linear-logic truth" can be derived from the semantics of computability logic.
Being semantically constructed, as yet computability logic does not have a fully developed proof theory. Finding deductive systems for various fragments of it and exploring their syntactic properties is an area of ongoing research.
References
- G. Japaridze, Introduction to computability logic. Annals of Pure and Applied Logic 123 (2003), pages 1–99.
- G. Japaridze, Propositional computability logic I. ACM Transactions on Computational Logic 7 (2006), pages 302-330.
- G. Japaridze, Propositional computability logic II. ACM Transactions on Computational Logic 7 (2006), pages 331-362.
- G. Japaridze, Introduction to cirquent calculus and abstract resource semantics. Journal of Logic and Computation 16 (2006), pages 489-532.
- G. Japaridze, Computability logic: a formal theory of interaction. Interactive Computation: The New Paradigm. D.Goldin, S.Smolka and P.Wegner, eds. Springer Verlag, Berlin 2006, pages 183-223.
- G. Japaridze, From truth to computability I. Theoretical Computer Science 357 (2006), pages 100-135.
- G. Japaridze, From truth to computability II. Theoretical Computer Science 379 (2007), pages 20–52.
- G. Japaridze, Intuitionistic computability logic. Acta Cybernetica 18 (2007), pages 77–113.
- G. Japaridze, The logic of interactive Turing reduction. Journal of Symbolic Logic 72 (2007), pages 243-276.
- G. Japaridze, The intuitionistic fragment of computability logic at the propositional level. Annals of Pure and Applied Logic 147 (2007), pages 187-227.
- G. Japaridze, Cirquent calculus deepened. Journal of Logic and Computation 18 (2008), No.6, pp. 983–1028.
- G. Japaridze, Sequential operators in computability logic. Information and Computation 206 (2008), No.12, pp. 1443–1475.
- G. Japaridze, Many concepts and two logics of algorithmic reduction. Studia Logica 91 (2009), No.1, pp. 1–24.
- G. Japaridze, In the beginning was game semantics. Games: Unifying Logic, Language and Philosophy. O. Majer, A.-V. Pietarinen and T. Tulenheimo, eds. Springer 2009, pp. 249–350.
- G. Japaridze, Towards applied theories based on computability logic. Journal of Symbolic Logic 75 (2010), pp. 565-601.
- I. Mezhirov and N. Vereshchagin, On abstract resource semantics and computability logic. Journal of Computer and System Sciences 76 (2010), pp. 356-372.
- N. Vereshchagin, Japaridze's computability logic and intuitionistic propositional calculus. Moscow State University, 2006.
External links
- Computability Logic Homepage
- Giorgi Japaridze
- Game Semantics or Linear Logic?
- Lecture Course on Computability Logic