English
For any x,y in G, x and y are inseparable iff x/y lies in the closure of {1}.
Русский
Для любых x,y в G, x и y неразделимы тогда и только тогда, когда x/y принадлежит замыканию множества {1}.
LaTeX
$$$\\operatorname{Inseparable}(x,y) \\iff x / y \\in \\overline{\\{1\\}}$$$
Lean4
@[to_additive]
theorem group_inseparable_iff {x y : G} : Inseparable x y ↔ x / y ∈ closure (1 : Set G) :=
by
rw [← singleton_one, ← specializes_iff_mem_closure, specializes_comm, specializes_iff_inseparable, ←
(Homeomorph.mulRight y⁻¹).isEmbedding.inseparable_iff]
simp [div_eq_mul_inv]