Premium
All Finitely Axiomatizable Normal Extensions of K4.3 are Decidable
Author(s) -
Zakharyaschevm Michael,
Alekseev Alexander
Publication year - 1995
Publication title -
mathematical logic quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.473
H-Index - 28
eISSN - 1521-3870
pISSN - 0942-5616
DOI - 10.1002/malq.19950410103
Subject(s) - decidability , mathematics , axiom , class (philosophy) , frame (networking) , argument (complex analysis) , discrete mathematics , modal logic , pure mathematics , modal , algebra over a field , computer science , geometry , telecommunications , biochemistry , chemistry , artificial intelligence , polymer chemistry
We use the apparatus of the canonical formulas introduced by Zakharyaschev [10] to prove that all finitely axiomatizable normal modal logics containing K4.3 are decidable, though possibly not characterized by classes of finite frames. Our method is purely frame‐theoretic. Roughly, given a normal logic L above K4.3, we enumerate effectively a class of (possibly infinite) frames with respect to which L is complete, show how to check effectively whether a frame in the class validates a given formula, and then apply a Harropstyle argument to establish the decidability of L , provided of course that it has finitely many axioms.
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom