\input zb-basic
\input zb-ioport
\iteman{io-port 01396691}
\itemau{Rimatskij, V.V.}
\itemti{Finite bases with respect to admissibility for modal logics of width 2.}
\itemso{Algebra Logika 38, No.4, 436-455 (1999); translation in Algebra Logic 38, No.4, 237-247 (1999).}
\itemab
Summary: It is proven that every finitely approximable and residually finite modal logic of depth 2 over K4 has a finite basis of admissible inference rules. This, in particular, implies that every finitely approximable residually finite modal logic of depth at most 2 is finitely based with respect to admissibility. (Among the logics of a larger depth or width, there are logics which do not have a finite, or even independent, basis of admissible rules of inference).
\itemrv{~}
\itemcc{}
\itemut{frame; finite basis of admissible inference rules; residually finite modal logic; finitely approximable modal logic}
\itemli{}
\end