Takahiro Seki
Title : An Algebraic Proof of the gamma-admissibility of Relevant Modal Logics
Abstract : The admissibility of Ackermannâ€™s rule gamma is one of the most
important problems in relevant logics. The gamma-admissibility was first
proved by an algebraic method. However, the development of Routleyâ€“Meyer
semantics and metavaluational techniques makes it possible to prove the
gamma-admissibility using methods that make use of normal models or
metavaluations, and the use of such methods is preferred. We discuss an
algebraic proof of the gamma-admissibility of relevant modal logics based
on modern algebraic models.