%r3_5.gl

true => lt(1,2),lt(2,3),lt(3,4),lt(4,5).

r(X,Y),r(Y,Z),r(X,Z) => goal. 
g(X,Y),g(Y,Z),g(X,Z) => goal. 

lt(X,Y),lt(Y,Z) => lt(X,Z).

lt(X,Y) => r(X,Y);g(X,Y).


%r(X,Y),g(X,Y) => false.  % not needed