7.7.8.0. isVar

Usage:

isVar(p); poly p

Return:

int

Purpose:

check, whether leading monomial of p is a power of a single variable
from the basering. Returns the exponent or 0 if p is multivariate.

LIB "freegb.lib";
ring r = 0,(x,y),dp;
poly f = xy+1;
isVar(f);
==> 0
poly g = y^3;
isVar(g);
==> 3
poly h = 7*x^3;
isVar(h);
==> 3
poly i = 1;
isVar(i);
==> 0