1,766 research outputs found
Arithmetical proofs of strong normalization results for symmetric lambda calculi
International audienceWe give arithmetical proofs of the strong normalization of two symmetric -calculi corresponding to classical logic. The first one is the -calculus introduced by Curien & Herbelin. It is derived via the Curry-Howard correspondence from Gentzen's classical sequent calculus LK in order to have a symmetry on one side between ``program'' and ``context'' and on other side between ``call-by-name'' and ``call-by-value''. The second one is the symmetric -calculus. It is the -calculus introduced by Parigot in which the reduction rule , which is the symmetric of , is added. These results were already known but the previous proofs use candidates of reducibility where the interpretation of a type is defined as the fix point of some increasing operator and thus, are highly non arithmetical
Investigations on the Dual Calculus
AbstractThe Dual Calculus, proposed recently by Wadler, is the outcome of two distinct lines of research in theoretical computer science:(A)Efforts to extend the Curry–Howard isomorphism, established between the simply-typed lambda calculus and intuitionistic logic, to classical logic.(B)Efforts to establish the tacit conjecture that call-by-value (CBV) reduction in lambda calculus is dual to call-by-name (CBN) reduction.This paper initially investigates relations of the Dual Calculus to other calculi, namely the simply-typed lambda calculus and the Symmetric lambda calculus. Moreover, Church–Rosser and Strong Normalization properties are proven for the calculus’ CBV reduction relation. Finally, extensions of the calculus to second-order types are briefly introduced
Strong Normalization for HA + EM1 by Non-Deterministic Choice
We study the strong normalization of a new Curry-Howard correspondence for HA
+ EM1, constructive Heyting Arithmetic with the excluded middle on
Sigma01-formulas. The proof-term language of HA + EM1 consists in the lambda
calculus plus an operator ||_a which represents, from the viewpoint of
programming, an exception operator with a delimited scope, and from the
viewpoint of logic, a restricted version of the excluded middle. We give a
strong normalization proof for the system based on a technique of
"non-deterministic immersion".Comment: In Proceedings COS 2013, arXiv:1309.092
Normalization of IZF with Replacement
ZF is a well investigated impredicative constructive version of
Zermelo-Fraenkel set theory. Using set terms, we axiomatize IZF with
Replacement, which we call \izfr, along with its intensional counterpart
\iizfr. We define a typed lambda calculus \li corresponding to proofs in
\iizfr according to the Curry-Howard isomorphism principle. Using realizability
for \iizfr, we show weak normalization of \li. We use normalization to prove
the disjunction, numerical existence and term existence properties. An inner
extensional model is used to show these properties, along with the set
existence property, for full, extensional \izfr
Semantics of a Typed Algebraic Lambda-Calculus
Algebraic lambda-calculi have been studied in various ways, but their
semantics remain mostly untouched. In this paper we propose a semantic analysis
of a general simply-typed lambda-calculus endowed with a structure of vector
space. We sketch the relation with two established vectorial lambda-calculi.
Then we study the problems arising from the addition of a fixed point
combinator and how to modify the equational theory to solve them. We sketch an
algebraic vectorial PCF and its possible denotational interpretations
A Normalizing Intuitionistic Set Theory with Inaccessible Sets
We propose a set theory strong enough to interpret powerful type theories
underlying proof assistants such as LEGO and also possibly Coq, which at the
same time enables program extraction from its constructive proofs. For this
purpose, we axiomatize an impredicative constructive version of
Zermelo-Fraenkel set theory IZF with Replacement and -many
inaccessibles, which we call \izfio. Our axiomatization utilizes set terms, an
inductive definition of inaccessible sets and the mutually recursive nature of
equality and membership relations. It allows us to define a weakly-normalizing
typed lambda calculus corresponding to proofs in \izfio according to the
Curry-Howard isomorphism principle. We use realizability to prove the
normalization theorem, which provides a basis for program extraction
capability.Comment: To be published in Logical Methods in Computer Scienc
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