∀ {α : Type u_1} {β : Type u_2} [inst : Field α] [inst_1 : LinearOrder α] [inst_2 : IsStrictOrderedRing α]
  [inst_3 : Ring β] {abv : β → α} [IsAbsoluteValue abv] {f g : ℕ → β},
  IsCauSeq abv f → IsCauSeq abv g → IsCauSeq abv (f * g)