fact: Definition root_head α {R : ring α} {K : field R} {acf : algeb_closed_field K} b n f L := if zerop_1st_n_const_coeff b f L then 0%ps else root_head_from_cγ_list f L b n 0.
imports: Utf8 QArith NPeano Sorting Misc Field2 Fpolynomial Fsummation Newton ConvexHull Power_series Puiseux_series Ps_add Ps_mul Ps_div PSpolynomial Puiseux_base AlgCloCharPol CharactPolyn F1Eq F1Prop Q_field PosOrder QbarM