%------------------------------------------------------------------------ % Program that gives wrong results. % % No simplification is possible (Model T = {q}, F = {p,r}, U = {}). %------------------------------------------------------------------------ % :- auto_table. :- table p/0, q/0, r/0. p :- tnot(q), p. q :- tnot(p). r :- tnot(q). %------------------------------------------------------------------------ test :- r, fail. test :- ( p -> ( tnot(p) -> writeln('p is undefined') ; writeln('p is true') ) ; writeln('p is false (OK)') ), ( q -> ( tnot(q) -> writeln('q is undefined') ; writeln('q is true (OK)') ) ; writeln('q is false') ), ( r -> ( tnot(r) -> writeln('r is undefined') ; writeln('r is true') ) ; writeln('r is false (OK)') ).