Non-commutative linear logic fragments with sub-context-free complexity

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Nishimiya, Yusaku, Taniguchi, Masaya
Formato: Preprint
Publicado: 2025
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866908626861424640
author Nishimiya, Yusaku
Taniguchi, Masaya
author_facet Nishimiya, Yusaku
Taniguchi, Masaya
contents We present new descriptive complexity characterisations of classes REG (regular languages), LCFL (linear context-free languages) and CFL (context-free languages) as restrictions on inference rules, size of formulae and permitted connectives in the Lambek calculus; fragments of the intuitionistic non-commutative linear logic with direction-sensitive implication connectives. Our identification of the Lambek calculus fragments with proof complexity REG and LCFL is the first result of its kind. We further show the CFL complexity of one of the strictly `weakest' possible variants of the logic, admitting only a single inference rule. The proof thereof, moreover, is based on a direct translation between type-logical and formal grammar and structural induction on provable sequents; a simpler and more intuitive method than those employed in prior works. We thereby establish a clear conceptual utility of the Cut-elimination theorem for comparing formal grammar and sequent calculus, and identify the exact analogue of the Greibach Normal Form in Lambek grammar. We believe the result presented herein constitutes a first step toward a more extensive and richer characterisation of the interaction between computation and logic, as well as a finer-grained complexity separation of various sequent calculi.
format Preprint
id arxiv_https___arxiv_org_abs_2511_02348
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-commutative linear logic fragments with sub-context-free complexity
Nishimiya, Yusaku
Taniguchi, Masaya
Logic in Computer Science
Computational Complexity
Formal Languages and Automata Theory
Logic
We present new descriptive complexity characterisations of classes REG (regular languages), LCFL (linear context-free languages) and CFL (context-free languages) as restrictions on inference rules, size of formulae and permitted connectives in the Lambek calculus; fragments of the intuitionistic non-commutative linear logic with direction-sensitive implication connectives. Our identification of the Lambek calculus fragments with proof complexity REG and LCFL is the first result of its kind. We further show the CFL complexity of one of the strictly `weakest' possible variants of the logic, admitting only a single inference rule. The proof thereof, moreover, is based on a direct translation between type-logical and formal grammar and structural induction on provable sequents; a simpler and more intuitive method than those employed in prior works. We thereby establish a clear conceptual utility of the Cut-elimination theorem for comparing formal grammar and sequent calculus, and identify the exact analogue of the Greibach Normal Form in Lambek grammar. We believe the result presented herein constitutes a first step toward a more extensive and richer characterisation of the interaction between computation and logic, as well as a finer-grained complexity separation of various sequent calculi.
title Non-commutative linear logic fragments with sub-context-free complexity
topic Logic in Computer Science
Computational Complexity
Formal Languages and Automata Theory
Logic
url https://arxiv.org/abs/2511.02348