Variables E K : {subfield L}.
Hypothesis galKE : galois K E.
Section IntermediateField.
Variable M : {subfield L}.
Hypothesis (sKME : (K <= M <= E)%VS) (nKM : normalField K M).

Lemma normalField_castM :
{in 'Gal(E / K) &, {morph normalField_cast : x y / (x * y)%g}}.