atom(X)
X
is an atom (an empty list is considered an atom).
atomic(X)
X
is an atom or number.
number(X)
X
is a number.
integer(X)
X
is an integer.
float(X)
X
is a real number.
var(X)
X
is unbound (a noninstantiated variable).
nonvar(X)
X
is bound.
X == Y
X
and Y
are identical (but do not unify them).
X \== Y
X
and Y
are not identical.


[End] 