Lab2AIF

maximum(X,Y,X):-
    X>=Y.
maximum(X,Y,Y):-
    X<Y.

min(X,Y,X):-
    X=<Y,
    !.
min(_,Y,Y).

abs2(X,X) :- X >= 0, !.
abs2(X,Y) :- Y is -X.

fib(0,X):-X is 0.
fib(1,X):-X is 1.
fib(X,Y):-
    X>=2,
    X_Prime is X-1,
    X_PrimeTwo is X-2,
    fib(X_Prime,Y_Prime),
    fib(X_PrimeTwo,Y_PrimeTwo),
    Y is Y_Prime+Y_PrimeTwo.

divisor(X,Y,Z):-