proposition: Lemma preserves_powers_help (a c : A) (n : nat) : f (Str_nth n (powers_help a c)) = Str_nth n (powers_help (f a) (f c)).
proof: Proof. rewrite 2!(Str_nth_powers_help _ id). rewrite rings.preserves_mult. now rewrite preserves_nat_pow. Qed.
imports: Coq.setoid_ring.Ring Coq.Arith.Factorial MathClasses.misc.workaround_tactics MathClasses.interfaces.abstract_algebra MathClasses.interfaces.additional_operations MathClasses.interfaces.orders MathClasses.interfaces.naturals MathClasses.interfaces.integers MathClasses.theory.nat_pow MathClasses.theory.int_pow MathClasses.theory.streams