@@ Linia 1: / Linia 1: @@
+====== Logic operators ======
+{{tag>operators logic}}
+===== Description =====
+Satisfiability of Boolean formule
+**Source**:  The Art of Prolog
+===== Download =====
+Program source code: {{logic_operators.pl}}
+===== Listing =====
+<code prolog>
+/*
+	satisfiable(Formula) :-
+		There is a true instance of the Boolean formula Formula.
+*/
+	:- op(950, xfx, [&]).
+	:- op(950, xfx, [|]).
+	:- op(900,  fx, [~]).
+	satisfiable(true).
+	satisfiable(X & Y) :- satisfiable(X), satisfiable(Y).
+	satisfiable(X | Y) :- satisfiable(X).
+	satisfiable(X | Y) :- satisfiable(Y).
+	satisfiable((~ X)) :-  invalid(Y).
+/*
+	invalid(Formula) :-
+		There is a false instance of the Boolean formula Formula.
+*/
+	invalid(false).
+	invalid(X | Y) :- invalid(X), invalid(Y).
+	invalid(X & Y) :- invalid(X).
+	invalid(X & Y) :- invalid(Y).
+	invalid((~ X)) :- satisfiable(X).
+%	Program 3.32: Satisfiability of Boolean formule
+</code>
+===== Comments =====

pl/prolog/pllib/logic_operators.txt · ostatnio zmienione: 2019/06/27 15:50 (edycja zewnętrzna)

AIwiki

Menu