Function: polresultant
Section: polynomials
C-Name: polresultant0
Prototype: GGDnD0,L,
Help: polresultant(x,y,{v},{flag=0}): resultant of the polynomials x and y,
 with respect to the main variables of x and y if v is omitted, with respect
 to the variable v otherwise. flag is optional, and can be 0: default,
 assumes that the polynomials have exact entries (uses the subresultant
 algorithm), 1 for arbitrary polynomials, using Sylvester's matrix, or 2:
 using a Ducos's modified subresultant algorithm

