arXiv subjects

Go Hashimoto

Publications and source records attributed to Go Hashimoto.

4 recordsLinked to original sources

arXiv2026

A formulation of D-institution using functor categories

Variables are a crucial element in logic and are also addressed in institution theory, an effort to axiomatize logic. In institution theory, we typically use extensions (signature morphisms) obtained from variables instead of introducing variables directly. While this approach appears simple at first glance because it does not introduce new structures, it often requires numerous conditions to describe variable structures, which can actually complicate the discussion. In this paper, we propose introducing variable structures directly by utilizing a generalization of category of functors. We define a category of predicate logics and formulate the introduction of compound sentences as a functor. We also introduce a proof system and prove a completeness theorem.

cs.LO↗

arXiv2026

Induction rules for Transition Algebra

Transition Algebra (TA) is a type of infinite logic introduced to discuss rewriting systems. The natural deductive proof systems already introduced in TA satisfy completeness for countable signatures. However, it lacks compactness, making it unsuitable for practical applications. This time, we will create a compact proof system by restricting the (Star) rule to induction. We will also use a sequent proof system instead of natural deduction. Furthermore, we will introduce a semantics that makes this system complete, and its application (a model-theoretic proof of Craig interpolation).

cs.LO↗

arXiv2026

Forcing and Interpolation in first-order hybrid Logic with rigid symbols

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 Craig interpolation property.

cs.LO↗

arXiv2025

Model-theoretic Forcing in Transition Algebra

We study L\"owenheim-Skolem and Omitting Types theorems in Transition Algebra, a logical system obtained by enhancing many sorted first-order logic with features from dynamic logic. The sentences we consider include compositions, unions, and transitive closures of transition relations, which are treated similarly to actions in dynamic logics to define necessity and possibility operators. We show that Upward L\"owenheim-Skolem theorem, any form of compactness, and joint Robinson consistency property fail due to the expressivity of transitive closures of transitions. In this non-compact many-sorted logical system, we develop a forcing technique method by generalizing the classical method of forcing used by Keisler to prove Omitting Types theorem. Instead of working within a single signature, we work with a directed diagram of signatures, which allows us to establish Downward L\"owenheim-Skolem and Omitting Types theorems despite the fact that models interpret sorts as sets, possibly empty. Building on a complete system of proof rules for Transition Algebra, we extend it with additional proof rules to reason about constructor-based and/or finite transition algebras. We then establish the completeness of this extended system for a fragment of Transition Algebra obtained by restricting models to constructor-based and/or finite transition algebras.

cs.LO↗