∀ (K : Type u) [inst : NontriviallyNormedField K] (L : Type v) [inst_1 : Field L] [inst_2 : Algebra K L]
  [hu : IsUltrametricDist K] [inst_3 : CompleteSpace K] (x : L) {E : Type u_2} [inst_4 : Field E] [inst_5 : Algebra K E]
  [inst_6 : Algebra L E] [IsScalarTower K L E] [Polynomial.IsSplittingField L E ((Polynomial.mapAlg K L) (minpoly K x))]
  [inst_9 : Algebra.IsAlgebraic K E],
  (spectralMulAlgNorm K E) ((algebraMap L E) x) ^ (minpoly K x).natDegree =
    (spectralMulAlgNorm K E) ((Polynomial.mapAlg K E) (minpoly K x)).roots.prod