[eclipse 10]: anti_unify(a, b, X).
X = _65
yes.
[eclipse 11]: anti_unify(a, a, X).
X = a
yes.
[eclipse 9]: anti_unify(foo(a,b,c), foo(b,b,b), X).
X = foo(_115, b, _98)
yes.
[eclipse 8]: anti_unify(foo(a,a,a), foo(b,b,b), X).
X = foo(_98, _98, _98)
yes.