English
For a Normal F E and χ an isomorphism, restricting χ to E commutes with algebra maps also restricting to K2, K1.
Русский
При Normal F E и изоморфизме χ ограничение χ на E коммутирует с ограничениями отображений на K2, K1.
LaTeX
$$$\alpha\_{E}^K(χ) = χ\restriction_E \circ α^K$$$
Lean4
theorem restrictNormal_trans [Normal F E] :
(χ.trans ω).restrictNormal E = (χ.restrictNormal E).trans (ω.restrictNormal E) :=
AlgEquiv.ext fun _ =>
(algebraMap E K₃).injective (by simp only [AlgEquiv.trans_apply, AlgEquiv.restrictNormal_commutes])