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A Resumption Monad Transformer and its Applications in the Semantics of Concurrency
, 2001
"... Resumptions are a valuable tool in the analysis and design of semantic models for concurrent programming languages, in which computations consist of sequences of atomic steps that may be interleaved. In this paper we consider a general notion of resumption, parameterized by the kind of computations ..."
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Resumptions are a valuable tool in the analysis and design of semantic models for concurrent programming languages, in which computations consist of sequences of atomic steps that may be interleaved. In this paper we consider a general notion of resumption, parameterized by the kind of computations that take place in the atomic steps. We define a monad transformer which, given a monad M that represents the atomic computations, constructs a monad R(M) for interleaved computations. Moreover, we use this monad transformer to define the denotational semantics of a simple imperative language supporting nondeterminism and concurrency.
A New Framework for Declarative Programming
, 2001
"... We propose a new indexedcategory syntax and semantics of Weak Hereditarily Harrop logic programming with constraints, based on resolution over taucategories:finite product categories with canonical structure. ..."
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Cited by 6 (3 self)
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We propose a new indexedcategory syntax and semantics of Weak Hereditarily Harrop logic programming with constraints, based on resolution over taucategories:finite product categories with canonical structure.
STABLE MEET SEMILATTICE FIBRATIONS AND FREE RESTRICTION CATEGORIES
"... Abstract. The construction of a free restriction category can be broken into two steps: the construction of a free stable semilattice fibration followed by the construction of a free restriction category for this fibration. Restriction categories produced from such fibrations are “unitary”, in a sen ..."
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Abstract. The construction of a free restriction category can be broken into two steps: the construction of a free stable semilattice fibration followed by the construction of a free restriction category for this fibration. Restriction categories produced from such fibrations are “unitary”, in a sense which generalizes that from the theory of inverse semigroups. Characterization theorems for unitary restriction categories are derived. The paper ends with an explicit description of the free restriction category on a directed graph. 1.
Some Characterization Results for Permutation Algebras
"... In recent years, many general presentations (metamodels) for calculi with namepassing, either operational or denotational in flavour, have been proposed. In this paper, we investigate the connections among some of these proposals, namely permutation algebras, named sets and sheaf categories, with t ..."
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Cited by 4 (1 self)
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In recent years, many general presentations (metamodels) for calculi with namepassing, either operational or denotational in flavour, have been proposed. In this paper, we investigate the connections among some of these proposals, namely permutation algebras, named sets and sheaf categories, with the aim of establishing a bridge between di#erent approaches to the abstract specification of nominal calculi. Key words: Semantics of programming languages; namepassing calculi; categorical and algebraic metamodels of languages.
About Permutation Algebras and Sheaves (and Named Sets, Too!)
, 2003
"... In recent years, many general presentations (metamodels) for calculi dealing with names, e.g. process calculi with namepassing, have been proposed. ..."
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Cited by 4 (3 self)
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In recent years, many general presentations (metamodels) for calculi dealing with names, e.g. process calculi with namepassing, have been proposed.
The Anticipatory and Systemic Adjointness of EScience Computation on the Grid, Computing Anticipatory Systems
 Proceedings CASYS‘01
, 2002
"... Abstract. Information systems are anticipatory systems providing knowledge of the real world. If escience is to operate reactively across the Grid it needs to be integrable with other information systems and ecommerce. Theory suggests that four stronganticipatory levels of computational types are ..."
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Abstract. Information systems are anticipatory systems providing knowledge of the real world. If escience is to operate reactively across the Grid it needs to be integrable with other information systems and ecommerce. Theory suggests that four stronganticipatory levels of computational types are sufficient to provide ultimate systemic closure with a single strong anticipation. Between the four levels are three layers of adjoint functors that relate each typepair. A free functor allows selection of a target type at a lower level and its right adjoint determines the higherlevel type. Because of the uniqueness a higherlevel anticipates a lower level and a lower level a higher. Type anticipation can be provided by left (F) or right (G) adjoint functors (F ⊣ G). These however are weak anticipation. Strong anticipation needs both left and right adjoints at each level or by composition of adjoints for the system as a whole ¯F ¯FF ⊣ G ¯G ¯G. The ISO standard for the Information Resource Dictionary System (IRDS) is itself an anticipatory system with this fourlevel architecture of universal types which can be used for design of interoperability across the Grid. The sufficiency of middleware tools for the Grid can be anticipated by reference to this same architecture. Thus for instance RDF, the Resource Description Framework, for the markup language XML seems to lack the top level abstraction of IRDS and to have only leftadjoint functionality and therefore not to qualify as a strong anticipatory system.
Fundamentals of Object Oriented Database Modelling
, 1996
"... Solid theoretical foundations of object oriented databases (OODBs) are still missing. The work reported in this paper contains results on a formally founded object oriented datamodel (OODM) and is intended to contribute to the development of a uniform mathematical theory of OODBs. A clear distinctio ..."
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Solid theoretical foundations of object oriented databases (OODBs) are still missing. The work reported in this paper contains results on a formally founded object oriented datamodel (OODM) and is intended to contribute to the development of a uniform mathematical theory of OODBs. A clear distinction between objects and values turns out to be essential in the OODM. Types and classes are used to structure values and objects repectively. This can be founded on top of any underlying type system. We outline different approaches to type systems and their semantics and claim that OODB theory on top of arbitrary type systems leads to type theory with topostheoretically defined semantics. On this basis the known solutions to the problems of unique object identification and genericity can be generalized. It turns out that extents of classes must be completely representable by values. Such classes are called valuerepresentable. As a consequence object identifiers degenerate to a pure...
The Type Concept in OODB Modelling and its Logical Implications
, 2000
"... Conceptual modelling requires a solid mathematical theory of concepts concerning the collection of concepts used in a specific, but broad enough field. The field considered in this paper is database modelling. Here object orientation in the widest sense has been identified as a unifying conceptual u ..."
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Conceptual modelling requires a solid mathematical theory of concepts concerning the collection of concepts used in a specific, but broad enough field. The field considered in this paper is database modelling. Here object orientation in the widest sense has been identified as a unifying conceptual umbrella that encompasses all relevant datamodels. The theory of object oriented databases has brought to light the fundamental distinction between the concepts of objects and values and correspondingly types and classes. This can be founded on top of any underlying type system. Thus, expressiveness of a datamodel basically depends on the type concept, from which the other concepts can be derived. In order to achieve a uniform mathematical theory we outline different type systems and their semantics and claim that OODB theory on top of arbitrary type systems leads to type theory with topostheoretically defined semantics. On this basis the known solutions to the problems of unique ...