English
Given S = T between intermediate fields of F E, there is an algebra isomorphism between S and T determined by that equality.
Русский
При S = T между промежуточными полями F E существует алгебраическое изоморфирование между S и T, определяемое данному равенству.
LaTeX
$$$\\text{equivOfEq} : (S=T) \\Rightarrow S \\simeq_A^F T$$$
Lean4
/-- Construct an algebra isomorphism from an equality of intermediate fields. -/
@[simps! apply]
def equivOfEq {S T : IntermediateField F E} (h : S = T) : S ≃ₐ[F] T :=
Subalgebra.equivOfEq _ _ (congr_arg toSubalgebra h)