Inhabitation for Non-idempotent Intersection Types

The inhabitation problem for intersection types in the lambda-calculus is known to be undecidable. We study the problem in the case of non-idempotent intersection, considering several type assignment systems, which characterize the solvable or the strongly normalizing lambda-terms. We prove the decidability of the inhabitation problem for all the systems considered, by providing sound and complete inhabitation algorithms for them

Bounding normalization time through intersection types

Non-idempotent intersection types are used in order to give a bound of the length of the normalization beta-reduction sequence of a lambda term: namely, the bound is expressed as a function of the size of the term.Comment: In Proceedings ITRS 2012, arXiv:1307.784

Introduction to linear logic and ludics, part II

This paper is the second part of an introduction to linear logic and ludics, both due to Girard. It is devoted to proof nets, in the limited, yet central, framework of multiplicative linear logic and to ludics, which has been recently developped in an aim of further unveiling the fundamental interactive nature of computation and logic. We hope to offer a few computer science insights into this new theory

A proof of strong normalisation using domain theory

Ulrich Berger presented a powerful proof of strong normalisation using domains, in particular it simplifies significantly Tait's proof of strong normalisation of Spector's bar recursion. The main contribution of this paper is to show that, using ideas from intersection types and Martin-Lof's domain interpretation of type theory one can in turn simplify further U. Berger's argument. We build a domain model for an untyped programming language where U. Berger has an interpretation only for typed terms or alternatively has an interpretation for untyped terms but need an extra condition to deduce strong normalisation. As a main application, we show that Martin-L\"{o}f dependent type theory extended with a program for Spector double negation shift.Comment: 16 page

Types as Resources for Classical Natural Deduction

We define two resource aware typing systems for the lambda-mu-calculus based on non-idempotent intersection and union types. The non-idempotent approach provides very simple combinatorial arguments - based on decreasing measures of type derivations - to characterize head and strongly normalizing terms. Moreover, typability provides upper bounds for the length of head-reduction sequences and maximal reduction sequences

Characterization of strong normalizability for a sequent lambda calculus with co-control

We study strong normalization in a lambda calculus of proof-terms with co-control for the intuitionistic sequent calculus. In this sequent lambda calculus, the management of formulas on the left hand side of typing judgements is “dual" to the management of formulas on the right hand side of the typing judgements in Parigot’s lambdamu calculus - that is why our system has first-class “co-control". The characterization of strong normalization is by means of intersection types, and is obtained by analyzing the relationship with another sequent lambda calculus, without co-control, for which a characterization of strong normalizability has been obtained before. The comparison of the two formulations of the sequent calculus, with or without co-control, is of independent interest. Finally, since it is known how to obtain bidirectional natural deduction systems isomorphic to these sequent calculi, characterizations are obtained of the strongly normalizing proof-terms of such natural deduction systems.The authors would like to thank the anonymous referees for their valuable comments and helpful suggestions. This work was partly supported by FCT—Fundação para a Ciência e a Tecnologia, within the project UID-MAT-00013/2013; by COST Action CA15123 - The European research network on types for programming and verification (EUTypes) via STSM; and by the Ministry of Education, Science and Technological Development, Serbia, under the projects ON174026 and III44006.info:eu-repo/semantics/publishedVersio