English
For any set s in M, the opposite of the closure of s equals the closure of the preimage of s under unop: (closure s).op = closure (unop^{-1} s).
Русский
Для множества s в M противоположность замыкания равна замыканию предварительного образа s под действием unop: (closure s).op = closure (unop^{-1} s).
LaTeX
$$$ (\mathrm{closure}(s))^{\mathrm{op}} = \mathrm{closure}(\operatorname{unop}^{-1} s) $$$
Lean4
@[to_additive]
theorem op_closure (s : Set M) : (closure s).op = closure (MulOpposite.unop ⁻¹' s) :=
by
simp_rw [closure, op_sInf, Set.preimage_setOf_eq, Submonoid.coe_unop]
congr with a
exact MulOpposite.unop_surjective.forall