Programacao Logica: um instrumento para o raciocinio

Logic programming has been explored ad recognized as a language suitable for knowledge representation and reasoning. On the other hand different nonmonotonic formalisms have been exploited as suitable formalizations of a common-sense reasoning. Unfortunately often these works have explored separately and apart, and defined upon different formal frame-works. Here we define a logic programming based framework encompassing some common-sense reasoning techniques. We introduce a model theory for logic programs based on a notion of assumption and the concept of reasoning from the consequences of assumption sets. Based on this semantics, common-sense reasoning is introduced as extensions to logic programs in a common framework. In this framework we show how belief revision is accommodated as reasoning from the possibly inconsistent meaning of the framework. It is shown how preferences between assumptions may be represented. De feasible reasoning is introduced as well as the ability to denote a preference among de feasible rules. Making hypothesis is often used as a common-sense reasoning technique and we introduce hypothetical reasoning. We show how reasoning from the classes of models can be denoted. Brave reasoning and skeptical reasoning are introduced as reasoning from a maximal sets of consequences and cautions reasoning as reasoning from maximal assumption sets. Example are shown illustrating the expressiveness of the Example are shown illustrating the expressiveness of the framework, proof the procedures were developed and its usage is also shownAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga