Categorical Proof-Theoretic Semantics

Fuente: arXiv
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Main Authors: Pym, David, Ritter, Eike, Robinson, Edmund
Format: Preprint
Published: 2023
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author Pym, David
Ritter, Eike
Robinson, Edmund
author_facet Pym, David
Ritter, Eike
Robinson, Edmund
contents In proof-theoretic semantics, model-theoretic validity is replaced by proof-theoretic validity. Validity of formulae is defined inductively from a base giving the validity of atoms using inductive clauses derived from proof-theoretic rules. A key aim is to show completeness of the proof rules without any requirement for formal models. Establishing this for propositional intuitionistic logic (IPL) raises some technical and conceptual issues. We relate Sandqvist's (complete) base-extension semantics of intuitionistic propositional logic to categorical proof theory in presheaves, reconstructing categorically the soundness and completeness arguments, thereby demonstrating the naturality of Sandqvist's constructions. This naturality includes Sandqvist's treatment of disjunction that is based on its second-order or elimination-rule presentation. These constructions embody not just validity, but certain forms of objects of justifications. This analysis is taken a step further by showing that from the perspective of validity, Sandqvist's semantics can also be viewed as the natural disjunction in a category of sheaves.
format Preprint
id arxiv_https___arxiv_org_abs_2302_09031
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Categorical Proof-Theoretic Semantics
Pym, David
Ritter, Eike
Robinson, Edmund
Logic
Logic in Computer Science
Category Theory
In proof-theoretic semantics, model-theoretic validity is replaced by proof-theoretic validity. Validity of formulae is defined inductively from a base giving the validity of atoms using inductive clauses derived from proof-theoretic rules. A key aim is to show completeness of the proof rules without any requirement for formal models. Establishing this for propositional intuitionistic logic (IPL) raises some technical and conceptual issues. We relate Sandqvist's (complete) base-extension semantics of intuitionistic propositional logic to categorical proof theory in presheaves, reconstructing categorically the soundness and completeness arguments, thereby demonstrating the naturality of Sandqvist's constructions. This naturality includes Sandqvist's treatment of disjunction that is based on its second-order or elimination-rule presentation. These constructions embody not just validity, but certain forms of objects of justifications. This analysis is taken a step further by showing that from the perspective of validity, Sandqvist's semantics can also be viewed as the natural disjunction in a category of sheaves.
title Categorical Proof-Theoretic Semantics
topic Logic
Logic in Computer Science
Category Theory
url https://arxiv.org/abs/2302.09031