Section FieldExtTheory.
Variables (F0 : fieldType) (L : fieldExtType F0).
Implicit Types (U V M : {vspace L}) (E F K : {subfield L}).
Canonical prodv_comoid := Monoid.ComLaw prodvC.

Lemma AHom_lker0 (rT : FalgType F0) (f : 'AHom(L, rT)) : lker f == 0%VS.