Main variable of a polynomial?

[Charles Greathouse <charles.greathouse@case.edu>]

Suppose I had a variable P which was a polynomial in some unknown
variable.  Is there a good way to get that variable in GP?

I suppose I could take the derivative until it was monic, subtract the
constant term, and divide by pollead.  But that hardly seems efficient
when the degree may be large.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University