## Interpolation in normal modal logics.(Russian)Zbl 0643.03012

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
Full Text: