This operator is used with the syntax
It returns the remainder when EXPRN1 is divided by EXPRN2. This is the true remainder based on the internal ordering of the variables, and not the pseudo-remainder. The pseudo-remainder and in general pseudo-division of polynomials can be calculated after loading the polydiv package. Please refer to the documentation of this package for details.
CAUTION: In the default case, remainders are calculated over the integers. If you need the remainder with respect to another domain, it must be declared explicitly.