English
The separating-left property is equivalent under a change of coordinates by a pair of linear equivalences.
Русский
Свойство разделения слева эквивалентно после смены координат двумя линейными эквивалентностями.
LaTeX
$$((e1.arrowCongr (e2.arrowCongr (LinearEquiv.refl R M)) B).SeparatingLeft) ↔ (B.SeparatingLeft)$$
Lean4
theorem congr (h : B.SeparatingLeft) : (e₁.arrowCongr (e₂.arrowCongr (LinearEquiv.refl R M)) B).SeparatingLeft :=
by
intro x hx
rw [← e₁.symm.map_eq_zero_iff]
refine h (e₁.symm x) fun y ↦ ?_
specialize hx (e₂ y)
simp only [LinearEquiv.arrowCongr_apply, LinearEquiv.symm_apply_apply, LinearEquiv.map_eq_zero_iff] at hx
exact hx