Provides a systematic introduction to the theory of logic programming and shows how this theory can be applied to reason about pure Prolog programs. The text includes an introduction to programming in Prolog and deals with such programming issues as determination, occur-check freedom and absence of errors. It covers both the natural interpretations of logic programming, as declarative specification and as procedure for computer execution.

This work introduces Prolog, beginning with the logical principles underlying the language, going on to explain how to apply these principles in the data structures of programming, how to utilize deduction and how to exercise control by means of lists, sets, recursion and operators.

The aim of this work is to develop a declarative semantics for N-Prolog with negation as failure. N-Prolog is an extension of Prolog proposed by Gabbay and Reyle, which allows for occurrences of nested implications in both goals and clauses. Our starting point is an operational semantics of the language defined by means of top-down derivation trees. Negation as finite failure can be naturally introduced in this context. A goal-G may be inferred from a database if every (...) top-down derivation of G from the database finitely fails, i.e., contains a failure node at finite height.Our purpose is to give a logical interpretation of the underlying operational semantics. In the present work we take into consideration only the basic problems of determining such an interpretation, so that our analysis will concentrate on the propositional case. Nevertheless we give an intuitive account of how to extend our results to a first order language. A full treatment of N-Prolog with quantifiers will be deferred to the second part of this work. (shrink)

An analysis of this allusive prologue demonstrates the poet’s acquaintance with all of Greek literature. The tone of his choliambic verses is softer and more urbane than that of his iambic predecessors, his message is less obtrusive, ambiguous and can only be grasped by an active interpretative effort. The linguistic and stylistic forming of the fables, which are consciously referring back to the prosaic and more polemic Aesop, is the core of the poet’s interest. With regard to content the poet (...) places himself within the tradition of divine revealed truth when he calls for justice and peaceful coexistence. But, through subtle hints he continues to make evident that a return to the Golden Age of the early days is neither possible nor actually desirable. (shrink)