Abstract:
The paper is devoted to the problem of interpolation in extensions
of the Johansson minimal logic J.
It is proved in [7] that the weak interpolation property
WIP is decidable over the minimal logic. In this case all logics
with WIP are divided into eight pairwise disjoint intervals. Tops of
these intervals, later called as etalon logics, possess a stronger
Craig's interpolation property CIP [7]. An
axiomatization and a semantic characterization for WIP-minimal
logics, that are the least logics of intervals, are found in [8]. The property CIP for six of the eight WIP-minimal
logics is stated in [8]. In this paper it will be
proved that the property CIP holds for the remaining two logics.
Thus all WIP-minimal logics possess the Craig interpolation property CIP.