English
If A is linearly disjoint from B and B′ ⊆ B, then A is linearly disjoint from B′.
Русский
Если A линейно разобщено с B, и B' ⊆ B, то A разобщено с B'.
LaTeX
$$$A' \perp B' \text{ if } A' ≤ A, B' ≤ B$$$
Lean4
/-- Similar to `IntermediateField.LinearDisjoint.of_le_right` but this is for abstract fields. -/
theorem of_le_right' (H : A.LinearDisjoint L) (L' : Type*) [Field L'] [Algebra F L'] [Algebra L' L]
[IsScalarTower F L' L] [Algebra L' E] [IsScalarTower F L' E] [IsScalarTower L' L E] : A.LinearDisjoint L' :=
by
refine Subalgebra.LinearDisjoint.of_le_right_of_flat H ?_
convert AlgHom.range_comp_le_range (IsScalarTower.toAlgHom F L' L) (IsScalarTower.toAlgHom F L E)
ext; exact IsScalarTower.algebraMap_apply L' L E _