On Blass Translation for Leśniewski’s Propositional Ontology and Modal Logics

Abstract

In this paper, we shall give another proof of the faithfulness of Blass translation (for short, B-translation) of the propositional fragment $$\mathbf{L}_1$$ of Leśniewski’s ontology in the modal logic $$\mathbf{K}$$ by means of Hintikka formula. And we extend the result to von Wright-type deontic logics, i.e., ten Smiley-Hanson systems of monadic deontic logic. As a result of observing the proofs we shall give general theorems on the faithfulness of B-translation with respect to normal modal logics complete to certain sets of well-known accessibility relations with a restriction that transitivity and symmetry are not set at the same time. As an application of the theorems, for example, B-translation is faithful for the provability logic $$\mathbf{PrL}$$ (= $$\mathbf{GL}$$ ), that is, $$\mathbf{K}$$ $$+$$ $$\Box (\Box \phi \supset \phi ) \supset \Box \phi $$ . The faithfulness also holds for normal modal logics, e.g., $$\mathbf{KD}$$ , $$\mathbf{K4}$$ , $$\mathbf{KD4}$$ , $$\mathbf{KB}$$ . We shall conclude this paper with the section of some open problems and conjectures.