English
Let i be an F-algebra hom E → K. Then the image of the algebraic closure of E over F under i is contained in the algebraic closure of K over F.
Русский
Пусть i — алгебрагоделение над F: E → K. Образ алгебраического замыкания E над F под отображением i содержится в алгебраическом замыкании K над F.
LaTeX
$$$ i\\left(\\operatorname{algebraicClosure}_F(E)\\right) \\subseteq \\operatorname{algebraicClosure}_F(K) $$$
Lean4
/-- If `i` is an `F`-algebra homomorphism from `E` to `K`, then the image of `algebraicClosure F E`
under the map `i` is contained in `algebraicClosure F K`. -/
theorem map_le_of_algHom (i : E →ₐ[F] K) : (algebraicClosure F E).map i ≤ algebraicClosure F K :=
map_le_iff_le_comap.2 (comap_eq_of_algHom i).ge