Logic Programming

The stable model semantics was recently generalized by Ferraris, Lee and Lifschitz to the full first-order language with a syntax translation approach that is very similar to McCarthy's circumscription. In this paper, we investigate the decidability and undecidability of various fragments of first-order language under both semantics of stable models and circumscription. Some maximally decidable classes and undecidable classes are identified. The results obtained in the paper show that the boundaries between decidability and undecidability for these two semantics are very different in spite of the similarity of definition. Moreover, for all fragments considered in the paper, decidability under the semantics of circumscription coincides with that in classical first-order logic. This seems rather counterintuitive due to the second-order definition of circumscription and the high undecidability of first-order circumscription.

Region-based memory management is an interesting compiletime memory management technique. Implementing region-based memory management for a language is twofold, firstly developing a static region analysis that annotates programs with region ...

This paper presents a computational model for the cooperation of constraint domains and an implementation for a particular case of practical importance. The computational model supports declarative programming with lazy and possibly higher-order functions, predicates, and the cooperation of different constraint domains equipped with their respective solvers, relying on a so-called constraint functional logic programming (CFLP) scheme. The implementation has been developed on top of theCFLPsystem, supporting the cooperation of the three domains ℋ, ℛ, and ℱ, which supply equality and disequality constraints over symbolic terms, arithmetic constraints over the real numbers, and finite domain constraints over the integers, respectively. The computational model has been proved sound and complete w.r.t. the declarative semantics provided by theCFLPscheme, while the implemented system has been tested with a set of benchmarks and shown to behave quite efficiently in comparison to the closes...

The paper reports on a study to develop solutions for a chosen problem in two related, but different languages. Moreover, the languages reflect two related, but different programming paradigms: logic programming, and constraint, logic programming, respectively. We use Prolog to describe calendars and their mutual conversions. Next, we use Prolog III to describe the same. We discuss suitability of both languages for this kind of task. Prolog III as a logic programming language with constraints allows writing a program which is both more general (i.e., covering a broader range of cases) and more abstract (i.e., expressed on a higher level of abstraction due to the use of constraints).

Pattern matching and unification are two key primitive operations used in many inference based systems including theorem provers, term rewriting systems, computer algebra systems, deductive data bases, Prolog, logic programming systems, functional language systems, systems for analysis of specifications and program synthesis, and program verification systems. In this note, we give results recently obtained in studying the complexity of matching and unification problems for first-order terms especially when some function symbols are interpreted. For further details and proofs, the reader may wish to refer to a forthcoming paper by the authors.

The present  work analyzes  potentialities  in  creative  synthesis  from  the  use  of  image  synthesizing  artificial intelligences  (AIs),  based  on  experiments  with  Midjourney,  Craiyon,  Dream  and  DALL-E,  carried  out  during  an interactive online debate with Technical High School students. It provides a report of the  educational experience, which included scientific divulgation, digital and computational literacy and media education, based on discussions and reflections on the concepts of intelligence, AI and natural intelligence (NI). The article presents a summary of the event, the impressions and productions of the participating public, as well as proposes the concept of creative synthesis as the production, by intelligent systems, of adaptive responses to the adversities placed. Education about and  with  AI  is  necessary  and urgent,  since  the  disruptions  caused  by  its  uses  are  already  impacting  all  strategic sectors  of  nations.  The  results  of  the  reported  experience  indicate  the  youth's  interest  in  understanding  and appropriating AI technologies.

We present a declarative framework for the compilation of constraint logic programs into variable-free relational theories which are then executed by rewriting. This translation provides an algebraic formulation of the abstract syntax of logic programs. Logic variables, unification, and renaming apart are completely elided in favor of manipulation of variable-free relation expressions. In this setting, term rewriting not only provides an operational semantics for logic programs, but also a simple framework for reasoning about program execution. We prove the translation sound, and the rewriting system complete with respect to traditional SLD semantics.