The verify(expr1,expr2,range) and verify(expr1,expr2,range(ver)) commands return true if it can be determined that the two ranges  and  satisfy a relation operandwise, either by testing with equality or by using the verification ver.

If true is returned, then each of endpoints satisfied the relation.

If false is returned, then at least one pair of endpoints did not satisfy the relation (a result of type verify(false)).

If FAIL is returned, then for at least one pair of endpoints it could not be determined whether they satisfied the relation (a result of type verify(FAIL)).

The verify(expr1,expr2,range) command is symmetric.

The verify(expr1,expr2,range(ver)) command is symmetric if and only if the verification ver is symmetric.

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