English
For submonoids N and N' of M, their supremum equals the closure of their underlying sets: N ⊔ N' = closure((N : Set M) ∪ (N' : Set M)).
Русский
Для подмоноидов N и N' в M их наибольшая верхняя граница равна замыканию от объединения соответствующих множеств: N ⊔ N' = closure((N : Set M) ∪ (N' : Set M)).
LaTeX
$$$N \\sqcup N' = \\operatorname{closure}((N : \\mathrm{Set} M) \\cup (N' : \\mathrm{Set} M))$$$
Lean4
@[to_additive]
theorem sup_eq_closure (N N' : Submonoid M) : N ⊔ N' = closure ((N : Set M) ∪ (N' : Set M)) := by
simp_rw [closure_union, closure_eq]