Interpolation in normal modal logics. (Russian) Zbl 0643.03012

Maksimova, L. L.

Mat. Issled. 98, 40-56 (1987).

Normal extensions (NE) of the modal logic K are examined as for Craig’s interpolation property (CIP) and “interpolation property with respect to deducibility” (IPD). The results take up some results published by the author; proofs of new results are given. They concern the cardinalities of the extensions with CIP (IPD), properties of these extensions (finite axiomatizability, finite approximability) and the sufficient condition for \(L_ 1\subset L_ 2\) \((L_ i\) from NE(K) or NE(K4)) having CIP.

Reviewer: P.Materna

MSC:

03B45	Modal logic (including the logic of norms)
03C40	Interpolation, preservation, definability

Keywords:

Normal extensions; modal logic K; interpolation; finite axiomatizability