A Segerberg-like connection between certain classes of propositional logics
Krystyna Mruczek-Nasieniewska, Marek Nasieniewski · 2013
In [5, 6] and [7] two classes of logics called K and R were considered. The idea is to treat the negation as “it is possible that not”. Equivalently, such a negation is understood as “it is not necessary” and comes from [2]. The use of the modal language force us to choose some modal logic. In [1] a logic called Z was formulated with the help of S5, the class K is obtained by the use of normal modal logics, while R is obtained by applying the idea to regular logics. In the present paper we will indicate connections between classes K and R, that mainly refer to a Segerberg theorem expressing a connection between normal and regular modal logics.