Welcome to SWI-Prolog (threaded, 64 bits, version 9.0.4)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.

For online help and background, visit https://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).

?- man(john).
true.

?- loves(john, mary).
true

?- loves(john, X).
X = mary ;
X = wine ;
X = john ;
X = mary ;
false.

?- loves(X, wine).
X = john ;
X = mary ;
false.

?- loves(X, Y).
X = john,
Y = mary ;
X = john,
Y = wine ;
X = mary,
Y = wine ;
X = Y, Y = john ;
X = john,
Y = mary ;
false.

?- add(s(s(s(o))), s(s(o)), X).
X = s(s(s(s(s(o))))).

?- add(s(s(s(o))), X, s(s(s(s(s(o)))))).
X = s(s(o)).

?- add(X, s(s(s(o))), s(s(s(s(s(o)))))).
X = s(s(o)) ;
false.

?- add(X, Y, s(s(s(s(s(o)))))).
X = o,
Y = s(s(s(s(s(o))))) ;
X = s(o),
Y = s(s(s(s(o)))) ;
X = s(s(o)),
Y = s(s(s(o))) ;
X = s(s(s(o))),
Y = s(s(o)) ;
X = s(s(s(s(o)))),
Y = s(o) ;
X = s(s(s(s(s(o))))),
Y = o ;
false.

?- add(X, Y, Z).
X = o,
Y = Z ;
X = s(o),
Z = s(Y) ;
X = s(s(o)),
Z = s(s(Y)) ;
X = s(s(s(o))),
Z = s(s(s(Y))) ;
X = s(s(s(s(o)))),
Z = s(s(s(s(Y)))) ;
X = s(s(s(s(s(o))))),
Z = s(s(s(s(s(Y))))) ;
X = s(s(s(s(s(s(o)))))),
Z = s(s(s(s(s(s(Y)))))) ;
X = s(s(s(s(s(s(s(o))))))),
Z = s(s(s(s(s(s(s(Y))))))) ;
X = s(s(s(s(s(s(s(s(o)))))))),
Z = s(s(s(s(s(s(s(s(Y)))))))) ;
X = s(s(s(s(s(s(s(s(s(o))))))))),
Z = s(s(s(s(s(s(s(s(s(Y))))))))) ;
X = s(s(s(s(s(s(s(s(s(s(...)))))))))),
Z = s(s(s(s(s(s(s(s(s(s(...)))))))))) ;
X = s(s(s(s(s(s(s(s(s(s(...)))))))))),
Z = s(s(s(s(s(s(s(s(s(s(...))))))))))

?- X = [1, 2].
X = [1, 2].

?- X = [1,2,3].
X = [1, 2, 3].

?- X = [].
X = [].

?- X = [1|[2|[3|[]]]].
X = [1, 2, 3].

?- [H|T] = [1,2,3].
H = 1,
T = [2, 3].

?- member(1, [1,2,3]).
true ;
false.

?- member(X, [1,2,3]).
X = 1 ;
X = 2 ;
X = 3.

?- member(1, X).
X = [1|_] ;
X = [_, 1|_] ;
X = [_, _, 1|_] ;
X = [_, _, _, 1|_] ;
X = [_, _, _, _, 1|_] ;
X = [_, _, _, _, _, 1|_]

?- member(X, Y).
Y = [X|_] ;
Y = [_, X|_] ;
Y = [_, _, X|_] ;
Y = [_, _, _, X|_] ;
Y = [_, _, _, _, X|_] ;
Y = [_, _, _, _, _, X|_] ;
Y = [_, _, _, _, _, _, X|_]