Collection Frames for Distributive Substructural Logics

Abstract

We present a new frame semantics for positive relevant and substructural propositional logics. This frame semantics is both a generalisation of Routley–Meyer ternary frames and a simplification of them. The key innovation of this semantics is the use of a single accessibility relation to relate collections of points to points. Different logics are modeled by varying the kinds of collections used: they can be sets, multisets, lists or trees. We show that collection frames on trees are sound and complete for the basic positive distributive substructural logic $\mathsf {B}^+$ , that collection frames on multisets are sound and complete for $\mathsf {RW}^+$ (the relevant logic $\mathsf {R}^+$ , without contraction, or equivalently, positive multiplicative and additive linear logic with distribution for the additive connectives), and that collection frames on sets are sound for the positive relevant logic $\mathsf {R}^+$ . The completeness of set frames for $\mathsf {R}^+$ is, currently, an open question.

Routes to relevance: Philosophies of relevant logics

“…39 39 In this respect, perhaps the algebraic semantics of Meyer and Routley (1972), the simplified semantics of Priest and Sylvan (1992), or the collection frames of Restall and Standefer (2023) make for even better candidates for establishing sufficiency. …”