The verify(expr1, expr2, listlist) and verify(expr1, expr2, listlist(ver)) calling sequences returns true if it can be determined that the two lists of lists satisfy the verification list or list(ver) operandwise.

If true is returned, then each of the pairs of operands of lists satisfied the relation. If false is returned, then at least one pair of operands of the inner lists did not satisfy the relation (a result of type verify(false)). Otherwise, FAIL is returned, indicating that for at least one pair of operands of the inner lists it could not be determined whether or not they satisfied the relation (a result of type verify(FAIL)).

The verifications verify(a, b, listlist) and verify(a, b, listlist(ver)) are equivalent to the calls verify(a, b, list(list)) and type(a, listlist) and type(b, listlist) and verify(a, b, list(list(ver))) and type(a, listlist) and type(b, listlist).

The verification listlist is symmetric and a verification listlist(ver) is symmetric if and only if the verification ver is symmetric.

If either expr1 or expr2 is not of type listlist then false is returned.