fact: Fixpoint ord_of_pt i pl := match pl with | [] => 0 | [(x, y) … pl₁] => if Qeq_dec (Qnat i) x then y else ord_of_pt i pl₁ end.
imports: Utf8 QArith NPeano Sorted ConvexHullMisc ConvexHull PolyConvexHull Field2 Misc Newton NbarM QbarM SplitList Fsummation Fpolynomial Power_series Puiseux_series Ps_add Ps_mul Ps_div Ps_add_compat PSpolynomial Puiseux_base CharactPolyn AlgCloCharPol