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23
Domain Theory
 Handbook of Logic in Computer Science
, 1994
"... Least fixpoints as meanings of recursive definitions. ..."
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Cited by 456 (20 self)
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Least fixpoints as meanings of recursive definitions.
Continuous Functions and Parallel Algorithms on Concrete Data Structures
 IN MFPS'91, L.N.C.S
, 1991
"... We report progress in two closely related lines of research: the semantic study of sequentiality and parallelism, and the development of a theory of intensional semantics. We generalize Kahn and Plotkin's concrete data structures to obtain a cartesian closed category of generalized concrete data str ..."
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Cited by 12 (2 self)
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We report progress in two closely related lines of research: the semantic study of sequentiality and parallelism, and the development of a theory of intensional semantics. We generalize Kahn and Plotkin's concrete data structures to obtain a cartesian closed category of generalized concrete data structures and continuous functions. The generalized framework continues to support a definition of sequential functions. Using this ccc as an extensional framework, we define an intensional framework  a ccc of generalized concrete data structures and parallel algorithms. This construction is an instance of a more general and more widely applicable categorytheoretic approach to intensional semantics, encapsulating a notion of intensional behavior as a computational comonad, and employing the coKleisli category as an intensional framework. We discuss the relationship between parallel algorithms and continuous functions, and supply some operational intuition for the parallel algorithms. We s...
Towards a theory of parallel algorithms on concrete data structures
 In Semantics for Concurrency, Leicester
, 1990
"... The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of DARPA or the U.S. government. Building on Kahn and Plotkin’s theory of concrete data structures and sequential functions, ..."
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Cited by 11 (6 self)
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The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of DARPA or the U.S. government. Building on Kahn and Plotkin’s theory of concrete data structures and sequential functions, Berry and Curien defined an intensional model of sequential algorithms between concrete data structures. In this paper we report on an attempt to develop a similar intensional model of concurrent computation. We present a notion of parallel algorithm between concrete data structures, together with suitable application and currying operations. We define an intensional strictness ordering on parallel algorithms, with respect to which application is well behaved (at first order types). We define the inputoutput function computed by a parallel algorithm, and we show that every parallel algorithm computes a continuous function. Thus, a parallel algorithm may be viewed as a continuous function together with a parallel computation strategy. In contrast, a Berry
Representation of Computations in Concurrent Automata by Dependence Orders
 THEORETICAL COMP. SCIENCE
, 1997
"... An automaton with concurrency relations A is a labeled transition system with a collection of binary relations indicating when two actions in a given state of the automaton can occur independently of each other. The concurrency relations induce a natural equivalence relation for finite computatio ..."
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Cited by 7 (2 self)
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An automaton with concurrency relations A is a labeled transition system with a collection of binary relations indicating when two actions in a given state of the automaton can occur independently of each other. The concurrency relations induce a natural equivalence relation for finite computation sequences. We investigate two graphtheoretic representations of the equivalence classes of computation sequences and obtain that under suitable assumptions on A they are isomorphic. Furthermore, the graphs are shown to carry a monoid operation reflecting precisely the composition of computations. This generalizes fundamental graphtheoretical representation results due to Mazurkiewicz in trace theory.
On the Model of Computation of Place/Transition Petri Nets
, 1994
"... . In the last few years, the semantics of Petri nets has been investigated in several different ways. Apart from the classical "token game", one can model the behaviour of Petri nets via nonsequential processes, via unfolding constructions, which provide formal relationships between nets and domain ..."
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Cited by 7 (2 self)
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. In the last few years, the semantics of Petri nets has been investigated in several different ways. Apart from the classical "token game", one can model the behaviour of Petri nets via nonsequential processes, via unfolding constructions, which provide formal relationships between nets and domains, and via algebraic models, which view Petri nets as essentially algebraic theories whose models are monoidal categories. In this paper we show that these three points of view can be reconciled. More precisely, we introduce the new notion of decorated processes of Petri nets and we show that they induce on nets the same semantics as that of unfolding. In addition, we prove that the decorated processes of a net N can be axiomatized as the arrows of a symmetric monoidal category which, therefore, provides the aforesaid unification. Introduction Petri nets, introduced by C.A. Petri in [18] (see also [21]), are a widely used model of concurrency. This model is attractive from a theoretical po...
A Cartesian Closed Category of Parallel Algorithms between Scott Domains
, 1991
"... We present a categorytheoretic framework for providing intensional semantics of programming languages and establishing connections between semantics given at different levels of intensional detail. We use a comonad to model an abstract notion of computation, and we obtain an intensional category fr ..."
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Cited by 6 (2 self)
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We present a categorytheoretic framework for providing intensional semantics of programming languages and establishing connections between semantics given at different levels of intensional detail. We use a comonad to model an abstract notion of computation, and we obtain an intensional category from an extensional category by the coKleisli construction; thus, while an extensional morphism can be viewed as a function from values to values, an intensional morphism is akin to a function from computations to values. We state a simple categorytheoretic result about cartesian closure. We then explore the particular example obtained by taking the extensional category to be Cont, the category of Scott domains with continuous functions as morphisms, with a computation represented as a nondecreasing sequence of values. We refer to morphisms in the resulting intensional category as algorithms. We show that the category Alg of Scott domains with algorithms as morphisms is cartesian closed. We...
Disjunctive Systems and LDomains
 Proceedings of the 19th International Colloquium on Automata, Languages, and Programming (ICALP’92
, 1992
"... . Disjunctive systems are a representation of Ldomains. They use sequents of the form X ` Y , with X finite and Y pairwise disjoint. We show that for any disjunctive system, its elements ordered by inclusion form an Ldomain. On the other hand, via the notion of stable neighborhoods, every Ldomain ..."
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Cited by 6 (2 self)
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. Disjunctive systems are a representation of Ldomains. They use sequents of the form X ` Y , with X finite and Y pairwise disjoint. We show that for any disjunctive system, its elements ordered by inclusion form an Ldomain. On the other hand, via the notion of stable neighborhoods, every Ldomain can be represented as a disjunctive system. More generally, we have a categorical equivalence between the category of disjunctive systems and the category of Ldomains. A natural classification of domains is obtained in terms of the style of the entailment: when jXj = 2 and jY j = 0 disjunctive systems determine coherent spaces; when jY j 1 they represent Scott domains; when either jXj = 1 or jY j = 0 the associated cpos are distributive Scott domains; and finally, without any restriction, disjunctive systems give rise to Ldomains. 1 Introduction Discovered by Coquand [Co90] and Jung [Ju90] independently, Ldomains form one of the maximal cartesian closed categories of algebraic cpos. Tog...