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Operationallybased theories of program equivalence
 Semantics and Logics of Computation
, 1997
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Un Calcul De Constructions Infinies Et Son Application A La Verification De Systemes Communicants
, 1996
"... m networks and the recent works of Thierry Coquand in type theory have been the most important sources of motivation for the ideas presented here. I wish to specially thank Roberto Amadio, who read the manuscript in a very short delay, providing many helpful comments and remarks. Many thanks also to ..."
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Cited by 16 (0 self)
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m networks and the recent works of Thierry Coquand in type theory have been the most important sources of motivation for the ideas presented here. I wish to specially thank Roberto Amadio, who read the manuscript in a very short delay, providing many helpful comments and remarks. Many thanks also to Luc Boug'e, who accepted to be my oficial supervisor, and to the chair of the jury, Michel Cosnard, who opened to me the doors of the LIP. During these last three years in Lyon I met many wonderful people, who then become wonderful friends. Miguel, Nuria, Veronique, Patricia, Philippe, Pia, Rodrigo, Salvador, Sophie : : : with you I have shared the happiness and sadness of everyday life, those little things which make us to remember someone forever. I also would like to thank the people from "Tango de Soie", for all those funny nights at the Caf'e Moulin Joly. Thanks too to the Uruguayan research community in Computer Science (specially to Cristina Cornes and Alberto Pardo) w
CoInductive Types in Coq: An Experiment with the Alternating Bit Protocol
, 1995
"... We describe an experience concerning the implementation and use of coinductive types in the proof editor Coq. Coinductive types are recursive types which, opposite to inductive ones, may be inhabited by infinite objects. In order to illustrate their use in Coq, we describe an axiomatisation of ..."
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We describe an experience concerning the implementation and use of coinductive types in the proof editor Coq. Coinductive types are recursive types which, opposite to inductive ones, may be inhabited by infinite objects. In order to illustrate their use in Coq, we describe an axiomatisation of a calculus of broadcasting systems where recursive processes are represented using infinite objects. This calculus is used for developing a verification proof of the alternating bit protocol. Keywords: Program Verification, Type Theory, CoInductive Types, Communicating Processes R'esum'e Dans cet article nous d'ecrivons une exp'erience concernant l'implantation et l'utilisation de types coinductifs dans l'environnement de preuves Coq. Les types coinductifs sont des types recursifs qui, `a la diff'erence des types inductifs, peuvent etre habit'es par des objets infinis. Pour illustrer leur utilisation dans Coq nous d'ecrivons comment axiomatiser un calcul de processus qui communiq...
Formal Neighbourhoods, Combinatory Böhm Trees, and Untyped Normalization by Evaluation
, 2008
"... We prove the correctness of an algorithm for normalizing untyped combinator terms by evaluation. The algorithm is written in the functional programming language Haskell, and we prove that it lazily computes the combinatory Böhm tree of the term. The notion of combinatory Böhm tree is analogous to th ..."
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We prove the correctness of an algorithm for normalizing untyped combinator terms by evaluation. The algorithm is written in the functional programming language Haskell, and we prove that it lazily computes the combinatory Böhm tree of the term. The notion of combinatory Böhm tree is analogous to the usual notion of Böhm tree for the untyped lambda calculus. It is defined operationally by repeated head reduction of terms to head normal forms. We use formal neighbourhoods to characterize finite, partial information about data, and define a Böhm tree as a filter of such formal neighbourhoods. We also define formal topology style denotational semantics of a fragment of Haskell following MartinLöf, and let each closed program denote a filter of formal neighbourhoods. We prove that the denotation of the output of our algorithm is the Böhm tree of the input term. The key construction in the proof is a ”glueing ” relation between terms and semantic neighbourhoods which is defined by induction on the latter. This relation is related to the glueing relation which was earlier used for proving the correctness of a normalization by evaluation algorithm for typed combinatory logic. 1
General Terms
"... We propose a new way to reason about general recursive functional programs in the dependently typed programming language Agda, which is based on MartinLöf’s intuitionistic type theory. We show how to embed an external programming logic, Aczel’s Logical Theory of Constructions (LTC) inside Agda. To ..."
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We propose a new way to reason about general recursive functional programs in the dependently typed programming language Agda, which is based on MartinLöf’s intuitionistic type theory. We show how to embed an external programming logic, Aczel’s Logical Theory of Constructions (LTC) inside Agda. To this end we postulate the existence of a domain of untyped functional programs and the conversion rules for these programs. Furthermore, we represent the inductive notions in LTC (intuitionistic predicate logic and totality predicates) as inductive notions in Agda. To illustrate our approach we specify an LTCstyle logic for PCF, and show how to prove the termination and correctness of a general recursive algorithm for computing the greatest common divisor of two numbers. Categories and Subject Descriptors F.3.1 [Logics and meanings of programs]: Specifying and Verifying and Reasoning about Programs–Logics of programs; D.2.4 [Software Engineering]:
External Examiner
, 2006
"... The results reported in Part III consist of joint work with Martín Escardó [14]. All the other results reported in this thesis are due to the author, except for background results, which are clearly stated as such. Some of the results in Part IV have already appeared as [28]. Note This version of th ..."
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The results reported in Part III consist of joint work with Martín Escardó [14]. All the other results reported in this thesis are due to the author, except for background results, which are clearly stated as such. Some of the results in Part IV have already appeared as [28]. Note This version of the thesis, produced on October 31, 2006, is the result of completing all the minor modifications as suggested by both the examiners in the viva report (Ref: CLM/AC/497773). We develop an operational domain theory to reason about programs in sequential functional languages. The central idea is to export domaintheoretic techniques of the Scott denotational semantics directly to the study of contextual preorder and equivalence. We investigate to what extent this can be done for two deterministic functional programming languages: PCF (Programminglanguage for Computable Functionals) and FPC (Fixed Point Calculus).