English
A variant of the map_starProjection statement: map_starProjection' expresses the same transfer under an isometry.
Русский
Вариант выражения переноса через изометрию.
LaTeX
$$map_starProjection' (f) p x = map_starProjection (f) p x (formal equality).$$
Lean4
theorem _root_.LinearIsometry.map_starProjection' {E E' : Type*} [NormedAddCommGroup E] [NormedAddCommGroup E']
[InnerProductSpace 𝕜 E] [InnerProductSpace 𝕜 E'] (f : E →ₗᵢ[𝕜] E') (p : Submodule 𝕜 E) [p.HasOrthogonalProjection]
[(p.map f).HasOrthogonalProjection] (x : E) : f (p.starProjection x) = (p.map f).starProjection (f x) :=
have : (p.map f.toLinearMap).HasOrthogonalProjection := ‹_›
f.map_starProjection p x