Example: ?- X is 2 ^ 3. /* Prolog symbol for power is ^ */ X = 8 ?- power(2,3,R). R = 8 ?- power(2,0,R). R = 1 /* our definion of ^ */ power(N,0,1):- !. power(N,K,R):- K1 is K-1,power(N,K1,R1),R is R1*N.