Products of modal logics. Part 2: Relativised quantifiers in classical logic
Products of modal logics. Part 2: Relativised quantifiers in classical logic
复制标题
模态逻辑的产物。
DOI:
10.1093/jigpal/8.2.165
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发表时间:
2000
期刊:
影响因子:
--
通讯作者:
V. Shehtman
中科院分区:
文献类型:
--
作者:
D. Gabbay;V. Shehtman
In the rst part of this paper we introduced products of modal logics and proved basic results on their axiomatisability and the f.m.p. In this continuation paper we prove a stronger result - the product f.m.p. holds for products of modal logics in which some of the modalities are reflexive or serial. This theorem is applied in classical rst-order logic; we identify a new Square Fragment (SF) of the classical logic, where the basic predicates are binary and all quantiers are relativised, and for which we show the f.m.p. in the classical sense. Also we prove that SF not included in Guarded Fragment (and in Packed Fragment) and that it can be embedded into the equational theory of relation algebras. 1