

% Need to program-compile M4 first.


Go("M4", "[Monday, Tuesday]", "x", answer).


Go("M4", "[Monday, y]", "[x, Tuesday]", answer).


Go("M4", "[Monday, Wednesday]", "[x, Tuesday]", answer).      % Fails


Go("M4", "x", "y", answer).            % Several answers


Go("M4", "x", "y", "{x/y}").           


Go("M4", "x", "y", "{y/x}").           


Go("M4", "x", "[x]", answer).          % Occur check

