Papers by Maria Yosefa Meo
Proceedings of the 3rd ACM SIGPLAN international conference on Principles and practice of declarative programming - PPDP '01, 2001
Theoretical Computer Science, 2020
Reasoning on a complex system in the abstract interpretation theory starts with a formal descript... more Reasoning on a complex system in the abstract interpretation theory starts with a formal description of the system behaviour specified by a collecting semantics. We take the common point of view that a collecting semantics is a very precise semantics from which other abstractions may be derived. We elaborate on both the concepts of precision and derivability, and introduce a notion of adequacy which tell us when a collecting semantics is a good choice for a given family of abstractions. We instantiate this approach to the case of first-order functional programs by considering three common collecting semantics and some abstract properties of functions. We study their relative precision and give a constructive characterization of the classes of abstractions which are adequate for the collecting semantics.
Onétudie tout d'abord la transformation intégrale qui permet d'étendre aux courants positifs ferm... more Onétudie tout d'abord la transformation intégrale qui permet d'étendre aux courants positifs fermés la définition des coordonnées de Chow des cycles effectifs de l'espace projectif.À un courant de bidegré (q, q) est associé un courant de bidegré (1, 1), obtenu par intégration sur les sous-espaces projectifs de dimension q − 1 et dont les potentiels jouent le rôle des formes de Chow. On vérifie que cette transformation est elle aussi injective. La démonstration repose, après utilisation d'un tranchage, sur une formule classique d'inversion de la transformation de Radon des fonctions.
Jurnal Pendidikan Dan Pembelajaran, Jun 26, 2013
Penelitian ini bertujuan untuk menjawab permasalahan tentang materi pembelajaran listening yang d... more Penelitian ini bertujuan untuk menjawab permasalahan tentang materi pembelajaran listening yang diperlukan oleh siswa semester genap kelas XI SMA Negeri 5 Pontianak. Penelitian ini juga bertujuan untuk mengetahui materi pembelajaran listening yang sesuai dengan pendekatan pembelajaran kontekstual. Sumber informasi dalam penelitian ini adalah guru mata pelajaran bahasa inggris SMA Negeri 5 Pontianak dan buku teks yang dipakai. hasil wawancara dan analisis buku teks diketahui bahwa materi pembelajaran listening yang digunakan di sekolah tersebut tidak memenuhi seluruh aspek CTL. Oleh karena itu peneliti mendesain materi pembelajaran listening dengan pendekatan kontekstual. Aktivitas dan kegiatan dalam desain materi tersebut di sesuaikan dengan aspek pendekatan pembelajaran kontesktual.
We define a semantic framework to reason about compositional properties of SLD-derivations and th... more We define a semantic framework to reason about compositional properties of SLD-derivations and their abstractions (observables). The framework allows us to address problems such as the relation between the (top-down) operational semantics and the (bottom-up) denotational semantics, the existence of a denotation for a set of definite clauses and their properties (compositionality w.r.t. various syntactic operators, correctness and minimality). This leads us to a flexible classification of the observables, where we can reason transition system. Using abstract interpretation techniques to model abstraction allows us to state very simple conditions on the observables which guarantee the validity of several general theorems. Keywords: SLD-derivations, abstract semantics, compositionality. 1
Electronic Notes in Theoretical Computer Science, 2016
We propose a new sharing analysis of object-oriented programs based on abstract interpretation. T... more We propose a new sharing analysis of object-oriented programs based on abstract interpretation. Two variables share when they are bound to data structures which overlap. We show that sharing analysis can greatly benefit from linearity analysis. We propose a combined domain including aliasing, linearity and sharing information. We use a graph-based representation of aliasing information which naturally encodes sharing and linearity information, and define all the necessary operators for the analysis of a Java-like language.
Proceedings Eighth International Symposium on Temporal Representation and Reasoning. TIME 2001
A temporal logic is presented for reasoning about the correctness of timed concurrent constraint ... more A temporal logic is presented for reasoning about the correctness of timed concurrent constraint programs. The logic is based on epistemic modalities which express either what a process knows at a certain time or what a process believes about the results of the other processes. In terms of these epistemic modalities of “knowledge ” and “belief” a compositional axiomatization is
in questo articolo si presentano i risultati di un progetto di ricerca di un gruppo interdiscipli... more in questo articolo si presentano i risultati di un progetto di ricerca di un gruppo interdisciplinare dell’Università degli Studi di Salerno e di Roma “La Sapienza” che, in continuità con studi precedenti, ha analizzato l’evoluzione degli incendi generati in gallerie stradali bidirezionali e la loro influenza sui processi di esodo attraverso simulazioni con codici di calcolo fluidodinamico e di evacuazione.
Lecture Notes in Computer Science, 2010
ABSTRACT The paper provides an overview of an approach to the semantics of (constraint) logic pro... more ABSTRACT The paper provides an overview of an approach to the semantics of (constraint) logic programs, whose aim is providing suitable theoretical bases for modeling observable properties of logic programs in a compositional way. The approach is based on the idea of choosing (either equivalence classes or abstractions of) sets of clauses as semantic domain and provides an uniform framework for defining different compositional semantics for logic programs, parametrically with respect to a given notion of observability. Since some observable properties have a natural definition which is dependent on the selection rule, the framework has been adapted to cope also with a suitable class of rules, which includes the leftmost selection rule. This provides a formal description of most of the observable properties of Prolog derivations and can therefore be viewed as reference semantics for Prolog transformation and analysis systems.
Lecture Notes in Computer Science, 2009
Constraint Handling Rules (CHR) is a general purpose, committedchoice declarative language which,... more Constraint Handling Rules (CHR) is a general purpose, committedchoice declarative language which, differently from other similar languages, uses multi-headed (guarded) rules. In this paper we prove that multiple heads augment the expressive power of the language. In fact, we first show that restricting to single head rules affects the Turing completeness of CHR, provided that the underlying signature (for the constraint theory) does not contain function symbols. Next we show that, also when considering generic constraint theories, under some rather reasonable assumptions it is not possible to encode CHR (with multi-headed rules) into a single-headed CHR language while preserving the semantics of programs. As a corollary we obtain that, under these assumptions, CHR can be encoded neither in (constraint) logic programming nor in pure Prolog.
Lecture Notes in Computer Science, 2003
ABSTRACT The verification of infinite state systems is one of the most challenging areas in the f... more ABSTRACT The verification of infinite state systems is one of the most challenging areas in the field of computer aided verification. In fact these systems arise naturally in many application fields, ranging from communication protocols to multi-threaded programs and time-dependent systems, and are quite difficult to analyze and to reason about. The main approaches developed so far consist in the extension to the infinite case of techniques already developed for finite state systems, notably model checking suitably integrated with abstractions which allow to finitely represent infinite sets of states. Constraints have also been quite useful in representing and manipulating infinite sets of states, both directly and indirectly. Particularly relevant in this context is the issue of compositionality: In fact, a compositional methodology could allow to reduce the complexity of the verification procedure by splitting a big system into smaller pieces. Moreover, when considering systems such as those arising in distributed and mobile computing, compositional verification is imperative in some cases, as the environment in which software agents operate cannot be fixed in advance. In this talk we will first illustrate some techniques based on constraints and multi set rewriting (MSR) for the automatic verification of systems and protocols parametric in several directions. Then we will discuss some ongoing research aiming at developing a compositional model for reasoning on MSR specifications.
Lecture Notes in Computer Science, 1998
We introduce a transformation system for concurrent constraint programming (CCP). We dene suitabl... more We introduce a transformation system for concurrent constraint programming (CCP). We dene suitable applicability conditions for the transformations which guarantee that the input/output CCP semantics is preserved also when distinguishing deadlocked computations from successful ones. The system allows to optimize CCP programs while preserving their intended meaning. Furthermore, since it preserves the deadlock behaviour of programs, it can be used for p roving deadlock freeness of a class of queries in a given program.
Lecture Notes in Computer Science, 2008
Constraint Handling Rules (CHR) is a declarative, committed-choice language which was originally ... more Constraint Handling Rules (CHR) is a declarative, committed-choice language which was originally specifically designed for writing constraint solvers [9] and which is nowadays a general purpose language. A CHR program consists of a set of guarded (simplification, propagation and ...
Lecture Notes in Computer Science
In this paper we study a declarative (fixpoint) semantics for logic programs which correctly mode... more In this paper we study a declarative (fixpoint) semantics for logic programs which correctly models several kinds of partial answers and call patterns. We first show how the -semantics [5,4] can model these observables when the selection rule is not taken into account. We then define a suitable immediate consequence operator, and hence a fixpoint semantics, for partial answers and
Proceedings of the 11th ACM SIGPLAN conference on Principles and practice of declarative programming - PPDP '09, 2009
Constraint Handling Rules (CHR) is a committed-choice declarative language which has been origina... more Constraint Handling Rules (CHR) is a committed-choice declarative language which has been originally designed for writing constraint solvers and which is nowadays a general purpose language. Recently the language has been extended by introducing userdefinable (static or dynamic) rule priorities. The resulting language, called CHR rp , allows a better control over execution while retaining a declarative and flexible style of programming. In this paper we study the expressive power of this language from the view point of the concurrency theory. We first show that dynamic priorities do not augment the expressive power by providing an encoding of dynamic priorities into static ones. Then we show that, when considering the theoretical operational semantics, CHR rp is strictly more expressive than CHR. This result is obtained by using a problem similar to the leader-election to show that, under some conditions, there exists no encoding of CHR rp into CHR. We also show, by using a similar technique, that the CHR language with the, so called, refined semantics is more expressive power than CHR with theoretical semantics and we extend some previous results showing that CHR can not be encoded into Prolog.
The purpose of this paper is to make a contribution towards the integration of Object-Orientation... more The purpose of this paper is to make a contribution towards the integration of Object-Orientation and logic programming. We i n troduce the notion of di erential programs, logic programs annotated to make their external interfaces explicit. Similarly to classes in the O-O paradigm, di erential programs can be organized in isa hierarchies. The isa-composition of di erential programs captures the semantics of several mechanisms such as static and dynamic overriding inheritance as well as a form of extension inheritance de ned in term of composition by union of clauses. The application of the programming discipline we propose is illustrated on a concrete programming example. We give a proof-theoretic semantics for isa-hierarchies: we de ne an inference system which extends SLD resolution to take i n to account the inheritance mechanisms encompassed by t h e isa operator. Then we i n troduce a corresponding operator which p r o vides a syntactic counterpart of the isa-composition. The new operator, denoted by <, transforms any isa hierarchy HP into an equivalent \ at" program HP / whose proof theoretic semantics is de ned in terms of the standard notion of SLD derivation. Finally we de ne a xed point semantics which i s <compositional and which models correctly the answer substitutions of programs. By virtue of the aforesaid correspondence between isa-hierarchies and <-composite programs, we obtain a compositional semantics for isa hierarchies. The semantics of di erential programs generalizes previous work on OR-compositional semantics for logic programs. It is obtained by resorting to the notion of context-sensitive interpretations, an extension of the-denotations of 3] de ned as sets of non-ground clauses.
Lecture Notes in Computer Science
In this paper we define a new compilative version of constructive negation (intensional negation)... more In this paper we define a new compilative version of constructive negation (intensional negation) in CLP and we prove its (nonground) correctness and completeness wrt the 3-valued completion. We show that intensional negation is essentially equivalent to constructive negation and that it is indeed more efficient, as one would expect from the fact that it is a compilative technique, with the transformation and the associated normalization process being performed once and for all on the source program. We define several formal non-ground semantics, based either on the derivation rule or on the least fixpoint of an immediate consequence operator. All these semantics are proved to correctly model the observable behavior, from the viewpoint of answer constraints. We give some equivalence theorems and we show that all our denotations are the non-ground representation of a single partial interpretation, which is 9 p 1" w, where ~p is the Fitting's operator [12].
International Conference on Logic Programming/Joint International Conference and Symposium on Logic Programming, 1991
ABSTRACT INTRODUCTION A semantics is compositional wrt a (syntactic) program composition operator... more ABSTRACT INTRODUCTION A semantics is compositional wrt a (syntactic) program composition operator ffi when the semantics of the compound construct C 1 ffi C 2 can be obtained by (semantically) composing the semantics of the constituents C 1 and C 2 . Compositionality is a desirable property since it allows to define in a modular way and incrementally the semantics of structured programs. Each time a new chunk of program is added, instead of defining Constructing Logic Programs, J.-M. Jacquet (editor) c fl1993 John Wiley &amp; Sons Ltd 2 AN OR-COMPOSITIONAL SEMANTICS FOR LOGIC PROGRAMS the semantics of the whole program from scratch, we can compose the semantics of the new piece of program with the semantics of the old one. As we will discuss in the following, this kind of compositionality provides the basis to develop semantic base
Uploads
Papers by Maria Yosefa Meo