Tableaux for essence and contingency
Giorgio Venturi, Pedro Teixeira Yago · Logic Journal of IGPL · 2020
Abstract We offer tableaux systems for logics of essence and accident and logics of non-contingency, showing their soundness and completeness for Kripke semantics. We also show an interesting parallel between these logics based on the semantic insensitivity of the two non-normal operators by which these logics are expressed.