Section FrobeniusAutomorphism.
Variables (p : nat) (charRp : p \in [char R]).
Canonical Frobenius_aut_additive := Additive Frobenius_aut_is_rmorphism.
Canonical Frobenius_aut_rmorphism := RMorphism Frobenius_aut_is_rmorphism.
End FrobeniusAutomorphism.

Lemma scaler_prodl (I : finType) (S : pred I) (F : I -> A) k :
\prod_(i in S) (k *: F i)  = k ^+ #|S| *: \prod_(i in S) F i.