English
Let α be an AddCommMonoid with a PartialOrder that is LocallyFinite and cancellative in addition. Then translating the right endpoint of an open interval preserves openness: (Ioo a b).image (· + c) = Ioo (a+c) (b+c).
Русский
Пусть α — добавочное моноидное множество; образ Ioo(a,b) при x↦x+c равен Ioo(a+c,b+c).
LaTeX
$$$\forall a,b,c:\alpha,\ (Ioo\ a\ b).image(\lambda x. x+c) = Ioo(a+c, b+c)$$$
Lean4
@[simp]
theorem image_add_right_Ioo (a b c : α) : (Ioo a b).image (· + c) = Ioo (a + c) (b + c) := by
rw [← map_add_right_Ioo, map_eq_image, addRightEmbedding, Embedding.coeFn_mk]