-
P
Q
- ,/2 (I)
P and then Q.
-
P
Q
- ;/2 (I)
P or Q.
- true
- true/0 (I)
Always succeeds.
-
X
Y
- =/2 (I)
Defined as if by the clause ``Z=Z'', i.e. X and Y are unified.
-
X
Y
-
\ =/2 (I)
Succeeds if X and Y are not unifiable,
fails if X and Y are unifiable.
It is thus equivalent to not(X = Y),
but is significantly more efficient.
-
X
Y
- ?=/2 (I)
Succeeds if X and Y are unifiable and fails if they are not,
but does not instantiate any variables.
Thus, it tests whether X and Y are unifiable.
Equivalent to
(
(X = Y)),
but is significantly more efficient.