
D.8.6.11 rootsMain
Procedure from library zeroset.lib (see zeroset_lib).
 Usage:
 rootsMain(f); where f is a polynomial
 Purpose:
 compute all roots of f in a finite extension of the ground field
without multiplicities.
 Return:
 list, all entries are polynomials
 _[1] = roots of f, each entry is a polynomial
_[2] = 'newA'  if the ground field is Q(b) and the extension field
is Q(a), then 'newA' is the representation of b in Q(a)
_[3] = minpoly of the algebraic extension of the ground field

 Assume:
 basering = Q[x,a] ideal mpoly must be defined, it might be 0!
 Note:
 might change the ideal mpoly!!
