Some additional axioms for t-normal logics. Defining K45, KB4, KD45 and S5 without using modal rules

Abstract

The paper will study extensions of t-normal logics S0.5o and S0.5 using some axioms of normal logics. We will prove determination theorems for these extensions by appropriate Kripke-style models. It will allow us to obtain the determinations of the logics K45, KB4 (= KB5), KD45 and S5 without using modal rules.