an:05817535
Zbl 1209.03011
Rybakov, Vladimir
Rules admissible in transitive temporal logic \(\mathrm{T}_{\mathrm{S}4}\), sufficient condition
EN
Theor. Comput. Sci. 411, No. 50, 4323-4332 (2010).
00270037
2010
j
03B44
temporal logic; inference rules; admissible rules
Summary: The paper develops a technique for computing inference rules admissible in temporal logic \(\text{T}_{\text{S}4}\). The problem whether there exists an algorithm recognizing inference rules admissible in \(\text{T}_{\text{S}4}\) is a long-standing open problem. The logic \(\text{T}_{\text{S}4}\) has neither the extension property nor the co-cover property which previously were central instruments for constructing decision algorithms for admissibility in modal logics (e.g., reflexive and transitive modal logic \(\text{S}4\)). Our paper uses a linear-compression property, a zigzag-ray property and a zigzag stretching property which hold for \(\text{T}_{\text{S}4}\). The main result of the paper is a sufficient condition for admissibility of inference rules in \(\text{T}_{\text{S}4}\). It is shown that all rules which are valid in special finite models (with an effective upper bound on size) must be admissible in \(\text{T}_{\text{S}4}\).