English
For any x,y,H,c,h as in the definition, mkSpanSingleton' x y H mapped on ⟨c·x,h⟩ equals c·y.
Русский
Для любых x,y,H,c,h из определения, mkSpanSingleton' x y H, применяемое к ⟨c·x,h⟩, равно c·y.
LaTeX
$$$\\mathrm{mkSpanSingleton}'(x,y,H)\\langle c\\cdot x,h\\rangle=c\\cdot y$$$
Lean4
@[simp]
theorem mkSpanSingleton'_apply (x : E) (y : F) (H : ∀ c : R, c • x = 0 → c • y = 0) (c : R) (h) :
mkSpanSingleton' x y H ⟨c • x, h⟩ = c • y :=
by
dsimp [mkSpanSingleton']
rw [← sub_eq_zero, ← sub_smul]
apply H
simp only [sub_smul, sub_eq_zero]
apply Classical.choose_spec (mem_span_singleton.1 h)