English
If p ⊕ q = E and M is any module, the projection map p.linearProjOfIsCompl q h is surjective onto range(p).
Русский
Если E разложено на p ⊕ q, то линейная проекция на p вдоль q расходится на p.
LaTeX
$$$\text{surjective}(p.linearProjOfIsCompl\ q\ h):\; \operatorname{range} p =\; \text{Im}(p.linearProjOfIsCompl q h).$$$
Lean4
@[simp]
theorem ofIsCompl_smul {R : Type*} [CommRing R] {E : Type*} [AddCommGroup E] [Module R E] {F : Type*} [AddCommGroup F]
[Module R F] {p q : Submodule R E} (h : IsCompl p q) {φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} (c : R) :
ofIsCompl h (c • φ) (c • ψ) = c • ofIsCompl h φ ψ :=
ofIsCompl_eq _ (by simp) (by simp)