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A Coinduction Principle for Recursively Defined Domains
 THEORETICAL COMPUTER SCIENCE
, 1992
"... This paper establishes a new property of predomains recursively defined using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest fixed point of a certain monotone operator ..."
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Cited by 40 (3 self)
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This paper establishes a new property of predomains recursively defined using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest fixed point of a certain monotone operator associated to D. This provides a structurally defined family of proof principles for these recursive predomains: to show that one element of D approximates another, it suffices to find a binary relation containing the two elements that is a postfixed point for the associated monotone operator. The statement of the proof principles is independent of any of the various methods available for explicit construction of recursive predomains. Following Milner and Tofte [10], the method of proof is called coinduction. It closely resembles the way bisimulations are used in concurrent process calculi [9]. Two specific instances of the coinduction principle already occur in work of Abramsky [2, 1] in the form of `internal full abstraction' theorems for denotational semantics of SCCS and the lazy lambda calculus. In the first case postfixed binary relations are precisely Abramsky's partial bisimulations, whereas in the second case they are his applicative bisimulations. The coinduction principle also provides an apparently useful tool for reasoning about equality of elements of recursively defined datatypes in (strict or lazy) higher order functional programming languages.
Computational Adequacy via `Mixed' Inductive Definitions
 In Mathematical Foundations of Programming Semantics, Proc. 9th Int. Conf
, 1994
"... . For programming languages whose denotational semantics uses fixed points of domain constructors of mixed variance, proofs of correspondence between operational and denotational semantics (or between two different denotational semantics) often depend upon the existence of relations specified as the ..."
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Cited by 22 (3 self)
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. For programming languages whose denotational semantics uses fixed points of domain constructors of mixed variance, proofs of correspondence between operational and denotational semantics (or between two different denotational semantics) often depend upon the existence of relations specified as the fixed point of nonmonotonic operators. This paper describes a new approach to constructing such relations which avoids having to delve into the detailed construction of the recursively defined domains themselves. The method is introduced by example, by considering the proof of computational adequacy of a denotational semantics for expression evaluation in a simple, untyped functional programming language. 1 Introduction It is well known that various domain constructors can be extended to act on relations on domains. For example, given binary relations R and S on domains D and E, there is a binary relation R!S on the domain of continuous functions D!E given by: (f; g) 2 (R!S) if and onl...
Topical Categories of Domains
, 1997
"... this paper are algebraic dcpos, and many of the points discussed here will be needed later in the special case. 2 They provide a simple example to illustrate the "Display categories" in Section 3.2 ..."
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Cited by 18 (17 self)
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this paper are algebraic dcpos, and many of the points discussed here will be needed later in the special case. 2 They provide a simple example to illustrate the "Display categories" in Section 3.2
Relational Properties of Recursively Defined Domains
 In 8th Annual Symposium on Logic in Computer Science
, 1993
"... This paper describes a mixed induction/coinduction property of relations on recursively defined domains. We work within a general framework for relations on domains and for actions of type constructors on relations introduced by O'Hearn and Tennent [20], and draw upon Freyd's analysis [7] of recurs ..."
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Cited by 15 (2 self)
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This paper describes a mixed induction/coinduction property of relations on recursively defined domains. We work within a general framework for relations on domains and for actions of type constructors on relations introduced by O'Hearn and Tennent [20], and draw upon Freyd's analysis [7] of recursive types in terms of a simultaneous initiality/finality property. The utility of the mixed induction/coinduction property is demonstrated by deriving a number of families of proof principles from it. One instance of the relational framework yields a family of induction principles for admissible subsets of general recursively defined domains which extends the principle of structural induction for inductively defined sets. Another instance of the framework yields the coinduction principle studied by the author in [22], by which equalities between elements of recursively defined domains may be proved via `bisimulations'. 1 Introduction A characteristic feature of higherorder functional lan...
Models of Lambda Calculi and Linear Logic: Structural, Equational and ProofTheoretic Characterisations
, 1994
"... Models of Lambda Calculi and Linear Logic: Structural, Equational and ProofTheoretic Characterisations Ralph Loader, of St. Hugh's College, Oxford. Thesis submitted for the Degree of D.Phil. Michaelmas term, 1994. T his thesis is an investigation into models of typed calculi and of linear logic. ..."
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Cited by 11 (0 self)
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Models of Lambda Calculi and Linear Logic: Structural, Equational and ProofTheoretic Characterisations Ralph Loader, of St. Hugh's College, Oxford. Thesis submitted for the Degree of D.Phil. Michaelmas term, 1994. T his thesis is an investigation into models of typed calculi and of linear logic. The models we investigate are denotational in nature; we construct various categories, in which types (or formulae) are interpreted by objects, and terms (proofs) by morphisms. The results we investigate compare particular properties of the syntax and the semantics of a calculus, by trying to use syntax to characterise features of a model, or vice versa. There are four chapters in the thesis, one each on linear logic and the simply typed calculus, and two on inductive datatypes. In chapter one, we look at some models of linear logic, and prove a full completeness result for multiplicative linear logic. We form a model, the linear logical predicates , by abstracting a little the structure ...
A Coinduction Principle for Recursively De ned Domains, Theoretical Computer Science
, 1992
"... This paper establishes a new property of predomains recursively de ned using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest xed point of a certain monotone operator ass ..."
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Cited by 5 (1 self)
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This paper establishes a new property of predomains recursively de ned using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest xed point of a certain monotone operator associated to D. This provides a structurally de ned family of proof principles for these recursive predomains: to show that one element of D approximates another, it su ces to nd a binary relation containing the two elements that is a post xed point for the associated monotone operator. The statement of the proof principles is independent of any of the various methods available for explicit construction of recursive predomains. Following Milner and Tofte [10], the method of proof is called coinduction. It closely resembles the way bisimulations are used in concurrent process calculi [9]. Two speci c instances of the coinduction principle already occur in work of Abramsky [2, 1] in the form of `internal full abstraction ' theorems for denotational semantics of SCCS and the lazy lambda calculus. In the rst case postxed binary relations are precisely Abramsky's partial bisimulations, whereas in the second case they are his applicative bisimulations. The coinduction principle also provides an apparently useful tool for reasoning about equality of elements of recursively de ned datatypes in (strict or lazy) higher order functional programming languages. 1
Computational Adequacy via `Mixed ' Inductive De nitions
"... Abstract. For programming languages whose denotational semantics uses xed points of domain constructors of mixed variance, proofs of correspondence between operational and denotational semantics (or between two di erent denotational semantics) often depend upon the existence of relations speci ed as ..."
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Abstract. For programming languages whose denotational semantics uses xed points of domain constructors of mixed variance, proofs of correspondence between operational and denotational semantics (or between two di erent denotational semantics) often depend upon the existence of relations speci ed as the xed point of nonmonotonic operators. This paper describes a new approach to constructing such relations which avoids having to delve into the detailed construction of the recursively de ned domains themselves. The method is introduced by example, by considering the proof of computational adequacy of a denotational semantics for expression evaluation in a simple, untyped functional programming language. 1