Publication Date:
2015-01-29
Description:
We present a contraction-free sequent calculus GS4 for the modal logic S4 such that all the rules are decreasing and enjoy the subformula property. We also introduce a refutation calculus RS4 with the same properties of GS4 . We provide a proof search algorithm that, given a sequent , returns either a proof of in GS4 or a refutation of in RS4 . From a refutation of , we can generate an S4 -model of .
Print ISSN:
0955-792X
Electronic ISSN:
1465-363X
Topics:
Computer Science
,
Mathematics
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