John R. Fisher

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The convex hull, Voronoi diagram and Delaunay triangulation are all essential concepts in computational geometry. Algorithms for solving the convex hull problem are commonly taught in an algorithms course, but the important relationship between convex hulls and the Voronoi diagram/Delaunay triangulation is usually not discussed. This paper presents Hull2VD,(More)
Logic programs with classical negation are defined • The analysis of these programs is based in a fundamental way upon the theory of sets of disjunctive clauses, which was the basis of theorem-proving theory in the 1960s and early 1970s. Like arbitrary sets of disjunctive clauses, these logic programs can be classically inconsistent, or unsatisfiable.(More)
This paper proposes a theory of action specifications using logic programs enhanced with actions. The intention of this is to provide an abstract theoretical framework for formal or semi-formal software specifications. The specifications themselves have a very natural logical form, and are relatively easy to work with, because of the highly declarative(More)
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