Cut-Elimination Theorem for Higher-Order Classical Logic: An Intuitionistic Proof

1987 ◽  
pp. 243-251 ◽  
Author(s):  
A. G. Dragalin
Keyword(s):  
Classical Logic ◽  
Higher Order ◽  
Cut Elimination

scholarly journals Call-by-name reduction and cut-elimination in classical logic

2008 ◽  
Vol 153 (1-3) ◽  
pp. 38-65 ◽  
Author(s):  
Kentaro Kikuchi
Keyword(s):  
Classical Logic ◽  
Cut Elimination

An untyped higher order logic with Y combinator

2007 ◽  
Vol 72 (4) ◽  
pp. 1385-1404
Author(s):  
James H. Andrews
Keyword(s):  
Model Theory ◽  
Lambda Calculus ◽  
Higher Order ◽  
Order Logic ◽  
Proof System ◽  
Cut Elimination ◽  
Higher Order Logic ◽  
Consistent Model

AbstractWe define a higher order logic which has only a notion of sort rather than a notion of type, and which permits all terms of the untyped lambda calculus and allows the use of the Y combinator in writing recursive predicates. The consistency of the logic is maintained by a distinction between use and mention, as in Gilmore's logics. We give a consistent model theory, a proof system which is sound with respect to the model theory, and a cut-elimination proof for the proof system. We also give examples showing what formulas can and cannot be used in the logic.

scholarly journals Topological completeness for higher-order logic

2000 ◽  
Vol 65 (3) ◽  
pp. 1168-1182 ◽  
Author(s):  
S. Awodey ◽  
C. Butz
Keyword(s):  
Classical Logic ◽  
Higher Order ◽  
Order Logic ◽  
Topological Spaces ◽  
Topological Semantics ◽  
Topos Theory ◽  
Higher Order Logic ◽  
High Type ◽  
Two Systems

AbstractUsing recent results in topos theory, two systems of higher-order logic are shown to be complete with respect to sheaf models over topological spaces—so-called “topological semantics”. The first is classical higher-order logic, with relational quantification of finitely high type; the second system is a predicative fragment thereof with quantification over functions between types, but not over arbitrary relations. The second theorem applies to intuitionistic as well as classical logic.

On categorical models of classical logic and the Geometry of Interaction

2007 ◽  
Vol 17 (5) ◽  
pp. 957-1027 ◽  
Author(s):  
CARSTEN FÜHRMANN ◽  
DAVID PYM
Keyword(s):  
Classical Logic ◽  
Disjoint Union ◽  
Sequent Calculus ◽  
Linear Logic ◽  
Structural Theory ◽  
Cut Elimination ◽  
Categorical Models ◽  
Boolean Lattices ◽  
Deep Exploration ◽  
Straightforward Proof

It is well known that weakening and contraction cause naive categorical models of the classical sequent calculus to collapse to Boolean lattices. In previous work, summarised briefly herein, we have provided a class of models calledclassical categoriesthat is sound and complete and avoids this collapse by interpreting cut reduction by a poset enrichment. Examples of classical categories include boolean lattices and the category of sets and relations, where both conjunction and disjunction are modelled by the set-theoretic product. In this article, which is self-contained, we present an improved axiomatisation of classical categories, together with a deep exploration of their structural theory. Observing that the collapse already happens in the absence of negation, we start with negation-free models calledDummett categories. Examples of these include, besides the classical categories mentioned above, the category of sets and relations, where both conjunction and disjunction are modelled by the disjoint union. We prove that Dummett categories are MIX, and that the partial order can be derived from hom-semilattices, which have a straightforward proof-theoretic definition. Moreover, we show that the Geometry-of-Interaction construction can be extended from multiplicative linear logic to classical logic by applying it to obtain a classical category from a Dummett category.Along the way, we gain detailed insights into the changes that proofs undergo during cut elimination in the presence of weakening and contraction.

scholarly journals A Binary Quantifier for Definite Descriptions for Cut Free Free Logics

Studia Logica ◽  
2021 ◽  
Author(s):  
Nils Kürbis
Keyword(s):  
Classical Logic ◽  
Final Section ◽  
Sequent Calculus ◽  
Definite Descriptions ◽  
Present Approach ◽  
Cut Elimination ◽  
Free Logic

AbstractThis paper presents rules in sequent calculus for a binary quantifier I to formalise definite descriptions: Ix[F, G] means ‘The F is G’. The rules are suitable to be added to a system of positive free logic. The paper extends the proof of a cut elimination theorem for this system by Indrzejczak by proving the cases for the rules of I. There are also brief comparisons of the present approach to the more common one that formalises definite descriptions with a term forming operator. In the final section rules for I for negative free and classical logic are also mentioned.

An intensional type theory: motivation and cut-elimination

2001 ◽  
Vol 66 (1) ◽  
pp. 383-400 ◽  
Author(s):  
Paul C Gilmore
Keyword(s):  
Type Theory ◽  
Proof Theory ◽  
Predicate Logic ◽  
Order Term ◽  
Higher Order ◽  
Cut Elimination ◽  
Consistency Proof ◽  
Completeness Proof ◽  
Higher Order Term

AbstractBy the theory TT is meant the higher order predicate logic with the following recursively defined types:(1) 1 is the type of individuals and [] is the type of the truth values:(2) [τ1…..τn] is the type of the predicates with arguments of the types τ1…..τn.The theory ITT described in this paper is an intensional version of TT. The types of ITT are the same as the types of TT, but the membership of the type 1 of individuals in ITT is an extension of the membership in TT. The extension consists of allowing any higher order term, in which only variables of type 1 have a free occurrence, to be a term of type 1. This feature of ITT is motivated by a nominalist interpretation of higher order predication.In ITT both well-founded and non-well-founded recursive predicates can be defined as abstraction terms from which all the properties of the predicates can be derived without the use of non-logical axioms.The elementary syntax, semantics, and proof theory for ITT are defined. A semantic consistency proof for ITT is provided and the completeness proof of Takahashi and Prawitz for a version of TT without cut is adapted for ITT: a consequence is the redundancy of cut.

Embedding theorems for LTL and its variants

2014 ◽  
Vol 25 (1) ◽  
pp. 83-134 ◽  
Author(s):  
NORIHIRO KAMIDE
Keyword(s):  
Intuitionistic Logic ◽  
Classical Logic ◽  
Linear Time ◽  
Cut Elimination ◽  
Embedding Theorems ◽  
Infinitary Logic ◽  
Spatial Logic ◽  
Linear Time Temporal Logic ◽  
Np Complete ◽  
Dynamic Topological Logic

In this paper, we prove some embedding theorems for LTL (linear-time temporal logic) and its variants:viz. some generalisations, extensions and fragments of LTL. Using these embedding theorems, we give uniform proofs of the completeness, cut-elimination and/or decidability theorems for LTL and its variants. The proposed embedding theorems clarify the relationships between some LTL-variations (for example, LTL, a dynamic topological logic, a fixpoint logic, a spatial logic, Prior's logic, Davies' logic and an NP-complete LTL) and some traditional logics (for example, classical logic, intuitionistic logic and infinitary logic).

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