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Operationallybased theories of program equivalence
 Semantics and Logics of Computation
, 1997
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A Variable Typed Logic of Effects
 Information and Computation
, 1993
"... In this paper we introduce a variable typed logic of effects inspired by the variable type systems of Feferman for purely functional languages. VTLoE (Variable Typed Logic of Effects) is introduced in two stages. The first stage is the firstorder theory of individuals built on assertions of equalit ..."
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Cited by 48 (12 self)
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In this paper we introduce a variable typed logic of effects inspired by the variable type systems of Feferman for purely functional languages. VTLoE (Variable Typed Logic of Effects) is introduced in two stages. The first stage is the firstorder theory of individuals built on assertions of equality (operational equivalence `a la Plotkin), and contextual assertions. The second stage extends the logic to include classes and class membership. The logic we present provides an expressive language for defining and studying properties of programs including program equivalences, in a uniform framework. The logic combines the features and benefits of equational calculi as well as program and specification logics. In addition to the usual firstorder formula constructions, we add contextual assertions. Contextual assertions generalize Hoare's triples in that they can be nested, used as assumptions, and their free variables may be quantified. They are similar in spirit to program modalities in ...
A Complete Characterization of Complete IntersectionType Theories (Extended Abstract)
 ACM TOCL
, 2000
"... M. DEZANICIANCAGLINI Universita di Torino, Italy F. HONSELL Universita di Udine, Italy F. ALESSI Universita di Udine, Italy Abstract We characterize those intersectiontype theories which yield complete intersectiontype assignment systems for lcalculi, with respect to the three canonical ..."
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Cited by 12 (5 self)
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M. DEZANICIANCAGLINI Universita di Torino, Italy F. HONSELL Universita di Udine, Italy F. ALESSI Universita di Udine, Italy Abstract We characterize those intersectiontype theories which yield complete intersectiontype assignment systems for lcalculi, with respect to the three canonical settheoretical semantics for intersectiontypes: the inference semantics, the simple semantics and the Fsemantics. Keywords Lambda Calculus, Intersection Types, Semantic Completeness, Filter Structures. 1 Introduction Intersectiontypes disciplines originated in [6] to overcome the limitations of Curry 's type assignment system and to provide a characterization of strongly normalizing terms of the lcalculus. But very early on, the issue of completeness became crucial. Intersectiontype theories and filter lmodels have been introduced, in [5], precisely to achieve the completeness for the type assignment system l" BCD W , with respect to Scott's simple semantics. And this result, ...
A Note on Logical Relations Between Semantics and Syntax
, 1997
"... This note gives a new proof of the `operational extensionality' property of Abramsky's lazy lambda calculusnamely the coincidence of contextual equivalence with a coinductively defined notion of `applicative bisimilarity'. This purely syntactic result is here proved using a logical relation (due ..."
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Cited by 9 (0 self)
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This note gives a new proof of the `operational extensionality' property of Abramsky's lazy lambda calculusnamely the coincidence of contextual equivalence with a coinductively defined notion of `applicative bisimilarity'. This purely syntactic result is here proved using a logical relation (due to Plotkin) between the syntax and its denotational semantics. The proof exploits a mixed inductive/coinductive characterisation of the logical relation recently discovered by the author.
Completeness of Intersection and Union Type Assignment Systems for CallByValue LambdaModels
"... We study a version of intersection and union type assignment system, unionelimination rule of which is allowed only when subject of its major premiss is a value of callbyvalue calculus. The system is shown to be sound and complete under some abstract notion of membership relation dened over simpl ..."
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Cited by 4 (0 self)
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We study a version of intersection and union type assignment system, unionelimination rule of which is allowed only when subject of its major premiss is a value of callbyvalue calculus. The system is shown to be sound and complete under some abstract notion of membership relation dened over simple semantics for callby value models, and to be invariant under callbyvalue conversion of subjects. We prove it by constructing a lter callbyvalue model. 1 Introduction Coppo et al. [5] introduced an intersection type assignment system as an extension of Curry's simple type assignment system (see [12, 11, 7] for expositions) to deal with the functional characters of solvable terms. In addition to the simple types constructed from typevariables and ! , the intersection types contain a typeconstant ! and types constructed by a constructor ^ (their intended meanings are universe and intersection of Partly supported by a GrantinAid for Scientic Research (C) No.09640253 o...
Game Semantics for the Pure Lazy λCalculus
 Proceedings of TLCA '01, number 2044 in LNCS
, 2001
"... In this paper we present a fully abstract game model for the pure lazy calculus, i.e. the lazy calculus without constants. In order to obtain this result we introduce a new category of games, the monotonic games, whose main characteristic consists in having an order relation on moves. ..."
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Cited by 1 (1 self)
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In this paper we present a fully abstract game model for the pure lazy calculus, i.e. the lazy calculus without constants. In order to obtain this result we introduce a new category of games, the monotonic games, whose main characteristic consists in having an order relation on moves.
Under consideration for publication in Math. Struct. in Comp. Science Towards Böhm trees for lambdavalue: the
, 2012
"... The pure lambda calculus has a wellestablished ‘standard theory ’ in which the notion of solvability characterises the operational relevance of terms. Solvable terms, defined as solutions to a betaequation, have a ‘syntactic ’ characterisation as terms with head normal form. Unsolvable terms are i ..."
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The pure lambda calculus has a wellestablished ‘standard theory ’ in which the notion of solvability characterises the operational relevance of terms. Solvable terms, defined as solutions to a betaequation, have a ‘syntactic ’ characterisation as terms with head normal form. Unsolvable terms are irrelevant and can be betaequated without affecting consistency. The derived notions of sensibility and Böhm trees connect the consistent theory with models and with a representation of approximate normal forms. The lambdavalue calculus is the calculus that corresponds to a strict functional programming language whose operational semantics is defined by the SECD machine. The betaequational definition of solvability has been duly adapted to the pure lambdavalue calculus, but the syntactic characterisation (value head normal forms and the ahead machine) involves beta reduction and not betavalue reduction. The vunsolvables terms cannot be equated without affecting consistency, and some vnormal forms are vunsolvable and have to be considered irrelevant. This has been ignored in the context of weak reduction (not going under lambda, an ingredient of callbyvalue reduction as specified by the SECD machine) because of the existence of initial models