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A Proof Theory for Generic Judgments
, 2003
"... this paper, we do this by adding the #quantifier: its role will be to declare variables to be new and of local scope. The syntax of the formula # x.B is like that for the universal and existential quantifiers. Following Church's Simple Theory of Types [Church 1940], formulas are given the type ..."
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Cited by 60 (14 self)
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this paper, we do this by adding the #quantifier: its role will be to declare variables to be new and of local scope. The syntax of the formula # x.B is like that for the universal and existential quantifiers. Following Church's Simple Theory of Types [Church 1940], formulas are given the type o, and for all types # not containing o, # is a constant of type (# o) o. The expression # #x.B is ACM Transactions on Computational Logic, Vol. V, No. N, October 2003. 4 usually abbreviated as simply # x.B or as if the type information is either simple to infer or not important
A proof theory for generic judgments: An extended abstract
 In LICS 2003
, 2003
"... A powerful and declarative means of specifying computations containing abstractions involves metalevel, universally quantified generic judgments. We present a proof theory for such judgments in which signatures are associated to each sequent (used to account for eigenvariables of the sequent) and t ..."
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Cited by 41 (15 self)
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A powerful and declarative means of specifying computations containing abstractions involves metalevel, universally quantified generic judgments. We present a proof theory for such judgments in which signatures are associated to each sequent (used to account for eigenvariables of the sequent) and to each formula in the sequent (used to account for generic variables locally scoped over the formula). A new quantifier, ∇, is introduced to explicitly manipulate the local signature. Intuitionistic logic extended with ∇ satisfies cutelimination even when the logic is additionally strengthened with a proof theoretic notion of definitions. The resulting logic can be used to encode naturally a number of examples involving name abstractions, and we illustrate using the πcalculus and the encoding of objectlevel provability.
Logic Programming and MultiAgent Systems: A Synergic Combination for Applications and Semantics
 IN THE LOGIC PROGRAMMING PARADIGM  A 25YEAR PERSPECTIVE
, 1999
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Induction and coinduction in sequent calculus
 Postproceedings of TYPES 2003, number 3085 in LNCS
, 2003
"... Abstract. Proof search has been used to specify a wide range of computation systems. In order to build a framework for reasoning about such specifications, we make use of a sequent calculus involving induction and coinduction. These proof principles are based on a proof theoretic (rather than sett ..."
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Cited by 23 (8 self)
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Abstract. Proof search has been used to specify a wide range of computation systems. In order to build a framework for reasoning about such specifications, we make use of a sequent calculus involving induction and coinduction. These proof principles are based on a proof theoretic (rather than settheoretic) notion of definition [13, 20, 25, 51]. Definitions are akin to (stratified) logic programs, where the left and right rules for defined atoms allow one to view theories as “closed ” or defining fixed points. The use of definitions makes it possible to reason intensionally about syntax, in particular enforcing free equality via unification. We add in a consistent way rules for pre and post fixed points, thus allowing the user to reason inductively and coinductively about properties of computational system making full use of higherorder abstract syntax. Consistency is guaranteed via cutelimination, where we give the first, to our knowledge, cutelimination procedure in the presence of general inductive and coinductive definitions. 1
Model checking for πcalculus using proof search
 CONCUR, volume 3653 of LNCS
, 2005
"... Abstract. Model checking for transition systems specified in πcalculus has been a difficult problem due to the infinitebranching nature of input prefix, namerestriction and scope extrusion. We propose here an approach to model checking for πcalculus by encoding it into a logic which supports rea ..."
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Cited by 15 (5 self)
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Abstract. Model checking for transition systems specified in πcalculus has been a difficult problem due to the infinitebranching nature of input prefix, namerestriction and scope extrusion. We propose here an approach to model checking for πcalculus by encoding it into a logic which supports reasoning about bindings and fixed points. This logic, called F Oλ ∆ ∇ , is a conservative extension of Church’s Simple Theory of Types with a “generic ” quantifier. By encoding judgments about transitions in picalculus into this logic, various conditions on the scoping of names and restrictions on name instantiations are captured naturally by the quantification theory of the logic. Moreover, standard implementation techniques for (higherorder) logic programming are applicable for implementing proof search for this logic, as illustrated in a prototype implementation discussed in this paper. The use of logic variables and eigenvariables in the implementation allows for exploring the state space of processes in a symbolic way. Compositionality of properties of the transitions is a simple consequence of the meta theory of the logic (i.e., cut elimination). We illustrate the benefits of specifying systems in this logic by studying several specifications of modal logics for picalculus. These specifications are also executable directly in the prototype implementation of F Oλ ∆ ∇. 1
Combining generic judgments with recursive definitions
 in "23th Symp. on Logic in Computer Science", F. PFENNING (editor), IEEE Computer Society Press, 2008, p. 33–44, http://www.lix.polytechnique.fr/Labo/Dale.Miller/papers/lics08a.pdf US
"... Many semantical aspects of programming languages are specified through calculi for constructing proofs: consider, for example, the specification of structured operational semantics, labeled transition systems, and typing systems. Recent proof theory research has identified two features that allow di ..."
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Cited by 14 (4 self)
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Many semantical aspects of programming languages are specified through calculi for constructing proofs: consider, for example, the specification of structured operational semantics, labeled transition systems, and typing systems. Recent proof theory research has identified two features that allow direct, logicbased reasoning about such descriptions: the treatment of atomic judgments as fixed points (recursive definitions) and an encoding of binding constructs via generic judgments. However, the logics encompassing these two features have thus far treated them orthogonally. In particular, they have not contained the ability to form definitions of objectlogic properties that themselves depend on an intrinsic treatment of binding. We propose a new and simple integration of these features within an intuitionistic logic enhanced with induction over natural numbers and we show that the resulting logic is consistent. The pivotal part of the integration allows recursive definitions to define generic judgments in general and not just the simpler atomic judgments that are traditionally allowed. The usefulness of this logic is illustrated by showing how it can provide elegant treatments of objectlogic contexts that appear in proofs involving typing calculi and arbitrarily cascading substitutions in reducibility arguments.
Automated Protocol Verification in Linear Logic
, 2002
"... In this paper we investigate the applicability of a bottomup evaluation strategy for a first order fragment of linear logic [7] for the purposes of automated validation of authentication protocols. Following [11], we use multiconclusion clauses to represent the behaviour of agents in a protocol ..."
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Cited by 14 (1 self)
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In this paper we investigate the applicability of a bottomup evaluation strategy for a first order fragment of linear logic [7] for the purposes of automated validation of authentication protocols. Following [11], we use multiconclusion clauses to represent the behaviour of agents in a protocol session, and we adopt the DolevYao intruder model and related message and cryptographic assumptions. Also, we use universal quantification to provide a logical and clean way to express creation of nonces. Our approach is well suited to verify properties which can be specified by means of minimality conditions. Unlike traditional approaches based on modelchecking, we can reason about parametric, infinitestate systems, thus we do not pose any limitation on the number of parallel runs of a given protocol. Furthermore, our approach can be used both to find attacks and to prove correctness of protocols. We present some preliminary experiments which we have carried out using the above approach.
Specifying RealTime FiniteState Systems in Linear Logic
 In 2nd International Workshop on Constraint Programming for TimeCritical Applications and MultiAgent Systems (COTIC
, 1998
"... Realtime finitestate systems may be specified in linear logic by means of linear implications between conjunctions of fixed finite length. In this setting, where time is treated as a dense linear ordering, safety properties may be expressed as certain provability problems. These provability proble ..."
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Cited by 12 (4 self)
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Realtime finitestate systems may be specified in linear logic by means of linear implications between conjunctions of fixed finite length. In this setting, where time is treated as a dense linear ordering, safety properties may be expressed as certain provability problems. These provability problems are shown to be in pspace. They are solvable, with some guidance, by finite proof search in concurrent logic programming environments based on linear logic and acting as sort of modelcheckers. One advantage of our approach is that either it provides unsafe runs or it actually establishes safety. 1 Introduction There are a number of formalisms for expressing realtime processes, including [1, 6, 7, 3, 4, 5, 50, 44, 45, 38]. Many of these realtime formalisms are based on temporal logic or its variations [46, 38, 33] or on timed process algebras [14, 42, 43, 23, 12], or on Buchi automata [52, 3]. In some cases exact complexitytheoretic information is available, such as [51, 3, 5], while ...
Relating StateBased and ProcessBased Concurrency through Linear Logic
, 2006
"... This paper has the purpose of reviewing some of the established relationships between logic and concurrency, and of exploring new ones. Concurrent and distributed systems are notoriously hard to get right. Therefore, following an approach that has proved highly beneficial for sequential programs, mu ..."
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Cited by 11 (1 self)
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This paper has the purpose of reviewing some of the established relationships between logic and concurrency, and of exploring new ones. Concurrent and distributed systems are notoriously hard to get right. Therefore, following an approach that has proved highly beneficial for sequential programs, much effort has been invested in tracing the foundations of concurrency in logic. The starting points of such investigations have been various idealized languages of concurrent and distributed programming, in particular the wellestablished statetransformation model inspired to Petri nets and multiset rewriting, and the prolific processbased models such as the πcalculus and other process algebras. In nearly all cases, the target of these investigations has been linear logic, a formal language that supports a view of formulas as consumable resources. In the first part of this paper, we review some of these interpretations of concurrent languages into linear logic. In the second part of the paper, we propose a completely new approach to understanding concurrent and distributed programming as a manifestation of logic, which yields a language that merges those two main paradigms of concurrency. Specifically, we present a new semantics for multiset rewriting founded on an alternative view of linear logic. The resulting interpretation is extended with a majority of linear connectives into the language of ωmultisets. This interpretation drops the distinction between multiset elements and rewrite rules, and considerably enriches the expressive power of standard multiset rewriting with embedded rules, choice, replication, and more. Derivations are now primarily viewed as open objects, and are closed only to examine intermediate rewriting states. The resulting language can also be interpreted as a process algebra. For example, a simple translation maps process constructors of the asynchronous πcalculus to rewrite operators, while the structural equivalence corresponds directly to logicallymotivated structural properties of ωmultisets (with one exception).
Encryption as an abstract datatype: An extended abstract
, 2003
"... At the DolevYao level of abstraction, security protocols can be specified using multisets rewriting. Such rewriting can be modeled naturally using proof search in linear logic. The linear logic setting also provides a simple mechanism for generating nonces and session and encryption keys via eigenv ..."
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Cited by 7 (2 self)
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At the DolevYao level of abstraction, security protocols can be specified using multisets rewriting. Such rewriting can be modeled naturally using proof search in linear logic. The linear logic setting also provides a simple mechanism for generating nonces and session and encryption keys via eigenvariables. We illustrate several additional aspects of this direct encoding of protocols into logic. In particular, encrypted data can be seen naturally as an abstract datatype. Entailments between security protocols as linear logic theories can be surprisingly strong. We also illustrate how the wellknown connection in linear logic between bipolar formulas and general formulas can be used to show that the asynchronous model of communication given by multiset rewriting rules can be understood, more naturally as asynchronous process calculus (also represented directly as linear logic formulas). The familiar proof theoretic notion of interpolants can also serve to characterize communication between a role and its environment.