Forcing and Interpolation in First-Order Hybrid Logic with rigid symbols
Daniel Găină, Go Hashimoto
TL;DR
The paper develops a forcing-based approach to Craig interpolation for a many-sorted first-order hybrid logic with rigid symbols, accommodating possibly empty domains. It dynamically extends signatures by adding new constants in a way that preserves consistency, and uses this to derive general CIP/RCP criteria via signature pushouts. The framework relies on institution-theoretic notions (signature morphisms, reducts, generated/reachable models) and yields a direct CIP proof for FOHLR that complements prior results. This contributes to modular specification and verification by clarifying when interpolation holds in complex many-sorted, hybrid logics with rigid symbols.
Abstract
In this paper, we establish an analogue of Craig Interpolation Property for a many-sorted variant of first-order hybrid logic. We develop a forcing technique that dynamically adds new constants to the underlying signature in a way that preserves consistency, even in the presence of models with possibly empty domains. Using this forcing method, we derive general criteria that are sufficient for a signature square to satisfy both Robinson's consistency and Craig interpolation properties.
