:: Checks whether two polynomial lists are equal or not as a set
return 0 or 1
plist1 plist2
This function checks whether plist1 and plist2 are equal or
not as a set .
For the same input and the same term ordering different
functions for Groebner basis computations may produce different outputs
as lists. This function compares such lists whether they are equal
as a generating set of an ideal.