CS 541 Lecture -*- Outline -*-

* Introduction to Logic Programming

** History
        1930s Herbrand and others develop proof procedures for pred. calculus
        1960 Prawitz introduces unification as aid to theorem proving
        1965 Robinson's resolution algorithm
        1973 first FORTRAN version of Prolog (U. Marseille-Aix, Colmerauer)
        1977 first Prolog compiler (Edinburgh, due to Warren)
			as fast as LISP!
        1981 Japanese adopt Prolog for fifth-generation computing effort

** Claims of Logic programming: (questions we'll look at)
        Algorithm = logic + control
                vs Algorithms + data structures = programs
        Specification = implementation
        Good for rapid prototyping (partly because it may be inefficient)
        Human-oriented (friendly)

** Logic programming techniques
***     nonprocedural, what is to be done, instead of how
***     proofs can be constructive
                to prove that there is an sorted version of list X,
                        exhibit the sorted version of the list
***     programs are propositions that assert existence of desired result
		the computation is a constructive proof
***     Think of programs as *relations*
                plus(X,Y,Z)     {<1,3,4>, <2,9,11>, ...}
                reverse(L1,L2)  {<[1,2,3], [3,2,1]>, ...}