Bulletin of the Section of Logic  

Xiao Long Xin, Rajab Ali Borzooei, Young Bae Jun

The notion of positive implicative soju ideal in BCK-algebra is introduced, and several properties are investigated. Relations between soju ideal and positive implicative soju ideal are considered, and characterizations of positive implicative soju ideal ... see more

Mitio Takano

The modal logic S4.2 is S4 with the additional axiom ??A ? ??A. In this article, the sequent calculus GS4.2 for this logic is presented, and by imposing an appropriate restriction on the application of the cut-rule, it is shown that, every GS4.2-provable ... see more

Lidia Typanska-Czajka

The only maximal extension of the logic of relevant entailment E is the classical logic CL. A logic L ? [E,CL] called pre-maximal if and only if L is a coatom in the interval [E,CL]. We present two denumerable infinite sequences of premaximal extensions o... see more

Dorota Leszczynska-Jasion, Yaroslav Petrukhin, Vasilyi Shangin, Marcin Jukiewicz

Kooi and Tamminga's correspondence analysis is a technique for designing proof systems, mostly, natural deduction and sequent systems. In this paper it is used to generate sequent calculi with invertible rules, whose only branching rule is the rule of cut... see more

Hasan Barzegar

The present note is an Erratum for the two theorems of the paper "Congruences and ideals in a distributive lattice with respect to a derivation" by M. Sambasiva Rao.