English
The opposite of the closure of a set s is the closure of its image under unop: closure(s)^{op} = closure(preimage unop s).
Русский
Противоположность замыкания множества равно замыканию образа обратного изображения.
LaTeX
$$$\\mathrm{closure}(s)^{op} = \\mathrm{closure}(\\mathrm{preimage}(\\mathrm{unop})\,s)$$$
Lean4
theorem op_closure (s : Set R) : (closure s).op = closure (MulOpposite.unop ⁻¹' s) :=
by
simp_rw [closure, op_sInf, Set.preimage_setOf_eq, coe_unop]
congr with a
exact MulOpposite.unop_surjective.forall