English
The intermediate field obtained from a Subalgebra via toIntermediateField and back yields the original Subalgebra: (S.toSubalgebra.toIntermediateField (fun _ => S.inv_mem)) = S.
Русский
Промежуточное поле, полученное из подалгебры через toIntermediateField и обратно, даёт исходную подалгебру: (S.toSubalgebra.toIntermediateField (fun _ => S.inv_mem)) = S.
LaTeX
$$$\big( S.toSubalgebra.toIntermediateField (\text{fun } _ \Rightarrow S.inv\_mem) \big) = S$$$
Lean4
@[simp]
theorem toIntermediateField_toSubalgebra (S : IntermediateField K L) :
(S.toSubalgebra.toIntermediateField fun _ => S.inv_mem) = S :=
by
ext
rfl