On the Coincidence of Semantics for Uniquely Determined Programs

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Conference Proceeding

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We study classes of logic programs, called here unique supported model classes or simply usm- classes, with the property that each member in the class is uniquely determined, that is, possesses a unique supported model. Known classes of uniquely determined programs include the acyclic and the acceptable programs, which have been much studied in the context of termination, and the authors gave a unifying treatment of these and other unique supported model classes in an earlier paper. In the present paper, we complement these earlier results by considering how various standard semantics relate to each other within certain unique supported model classes. In particular, we introduce the natural usm-class of all Φ-accessible programs, which contains the aforementioned classes, and has the property that, for each member of it, the stable, well-founded and weakly perfect-a models all coincide.


Presented at the First Irish Conference on the Mathematical Foundations of Computer Science and Information Technology, Cork, Ireland, July 20-21, 2000.