A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... If the observable is successful derivations, OR compositionality can be understood in logical terms since the set of all the (Herbrand) models is OR compositional [30] and correct wrt successful derivations) The only OR compositional semantics correct wrt computed answers are described in [24, 9, 8], while all the other OR compositional semantics [26, 33, 31, 30, 23] are only correct wrt successful derivations. Clearly, compositionality wrt program composition operators is a desirable property since it allows to define in a modular way and incrementally the semantics of structured programs. ....

....the modular analysis and transformation of programs. Over the last few years we have developed a general approach to the semantics [21, 7] whose 2 aim was modeling the observable behaviors (possibly in a compositional way) for a variety of logic languages, ranging from positive logic programs [17, 9, 8] to constraint logic programs [20, 19] and general logic programs [35] Our approach is based on the idea of choosing (equivalence classes of) sets of clauses as semantic domains. Denotations (that we call interpretations) are not interpretations in the conventional mathematical logic sense and ....

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A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

.... X = b is in the semantics of P 1 [ P 2 . Such an information is expressed by the clause q(X) true2p(X) Therefore, compositionality w.r.t. union of programs can be obtained by choosing a semantic domain based on clauses. This idea was first introduced in [24] and then further studied in 22 [8, 7] for the case of pure logic programs. In the following we show the application to CLP of this idea, essentially by lifting the definitions in [7] to the realm of constraints. Other compositional semantics based on a functional definition (e.g. the TP function) could be lifted from pure logic ....

A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

.... If the observable is successful derivation, OR compositionality can be understood in logical terms since the set of all the (Herbrand) models is OR compositional [24] and correct wrt successful derivations) The only OR compositional semantics correct wrt computed answers are described in [19, 5, 4]. Clearly, OR compositionality is a desirable property both for theoretical (compositional semantics of modules) and for practical (modular program analysis and transformation) purposes. Over the last few years we have developed a general approach to the semantics [13] whose aim was modeling the ....

....(modular program analysis and transformation) purposes. Over the last few years we have developed a general approach to the semantics [13] whose aim was modeling the observable behaviors (possibly in a compositional way) for a variety of logic languages, ranging from positive logic programs [10, 11, 5, 4], to general logic programs [26, 16] constraint logic programs [12] and concurrent constraint programs [14] Our approach is based on the idea of choosing (equivalence classes of) sets of clauses as semantic domains. Denotations (that we call interpretations) are not interpretations in the ....

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A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conf. on Logic Programming, pages 95--109, 1991.

....Programs Having established the equivalence between isa hierarchies and composite programs, we move on to study a compositional semantics for the class of differential programs. The approach we follow is inspired by the work on the semantics of open logic programs developed in [3, 4] and [5]. Similarly to differential programs, open logic programs are understood as program components rather than stand alone programs: their composition is performed taking the union of the components clauses. The work on the semantics of open logic programs was motivated by the fact that the standard ....

....of that interpretation. Functional semantics for logic program have been largely investigated in the literature: the semantics based on the T P operator of [21] and on the closure operator (T P id) of [18] are examples of such definitions. The semantics for open logic programs of [3, 4] and [5] is in some respects 15 similar to the definition based on the semantics (T P id) of [18] but it refines it in that: i) it captures the operational behaviour of programs more precisely (it is proved cas correct) and (ii) it provides a syntactic representation of the semantics (T P ....

A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

....[ Delta [ Theta) then G fails both in the hierarchy HP and in the corresponding program HP . 3 A semantics compositional wrt The approach we follow towards a compositional semantics for the composition operator is based on an extension of the semantics for open logic programs defined in [3] and [2] The extension had been motivated by the fact that the standard approach to the semantics of logic programming provides an elegant way of defining the meaning of programs but lacks an important compositionality property. The minimal model semantics ( 29] is in fact concerned only with ....

....operator ( 22] If we want a semantics expressed within program syntax, compositionality with respect to union of programs can be equivalently achieved by choosing sets of clauses as the semantic objects used to interpret our programs. This idea is at the basis of the open semantics proposed in [3] and [2] and similarly of the semantics de364 fined in [12] Roughly, the open semantics S(P ) of a program P , is given by the set of resultants [21] obtained from goals of the form p( X) in P . Namely S(P ) fp( X)#: B j 9 # s:t: p( X) # ;P Bg Under this definition, the ....

A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

....that they give a complete characterization of the program behavior for any goal. ffl syntactic domains make possible the definition of a unique denotation in cases where there exists no unique representative Herbrand model. Examples are the compositional semantics for positive logic programs [62, 63, 22, 21], whose domains are sets of clauses (see section 4) the semantic kernel for normal logic programs [43, 75] whose domains are sets of negative normal clauses (see section 6.3) the model state semantics for disjunctive logic programs [98, 90] whose domains are sets of positive ....

....classes of) clauses as a representation of one such a function, modeling the successful derivations [62] and the computed answers [63] observables. This idea fits quite naturally within the s semantics approach since the semantic domains are syntactic objects, i.e. programs. The Omega semantics [22, 21] is similar to one of the semantics in [62] yet it is defined according to the general s semantics approach. It was originally defined for a more general composition operator [ Omega , defined on Omega Gamma 3 en programs. An Omega open program [22] P is a positive program in which the ....

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A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

....Functional semantics for logic program have been already investigated in the literature: the TP operator of [17] and the closure operator (T P id) 15] are examples of such semantics. The approach we follow here is inspired by the work on of open logic programs developed in [6] and [7]. For the ground case, the semantics for open logic programs is in several respects similar to the semantics based on (T P id) of [15] but it refines it in that it provides a syntactic representation of the closure operator, a kind of normal form representation for (T P id) Like ....

A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95--109, 1991.

....described in [15] the semantics is based on a domain which consists of sets of (equivalence classes of) clauses. We first define an operational version O Omega (P ) of the semantics and we prove its compositionality. Then we show a fixpoint semantics F Omega (P ) originally introduced in [5], and we prove its equivalence to the operational semantics. From the model theoretic viewpoint, the compositional semantics is mapped onto a set of Herbrand interpretations, thus leading to a definition of Omega model and to a model theoretic semantics which are still based on the classical ....

....obtained by composing the denotation I P (considered as an open program) with a definition for the open predicates. This leads to a definition of Omega Gamma 3 del based on the classical notion of truth and which is compositional wrt program union. A different approach is followed in [11] and in [5] where models are based on an ad hoc notion of truth. The present chapter is a restricted version of [3] The reader is addressed to [3] as well as to [5, 4] for a complete treatment. The remaining of this chapter is organized as follows. In section 1.2 we define the operational semantics ....

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A. Bossi and M. Menegus. Una Semantica Composizionale per Programmi Logici Aperti. In P. Asirelli, editor, Proc. Sixth Italian Conference on Logic Programming, pages 95-- 109, 1991.

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