English
Under commutativity assumptions, the centralizer of any S is the whole ambient set.
Русский
При заданных условиях коммутативности, центральизатор любого S равен всему множеству.
LaTeX
$$$ \mathrm{centralizer}(S) = \mathrm{univ} $ under commutativity assumptions$$
Lean4
@[to_additive (attr := simp) addCentralizer_univ]
theorem centralizer_univ : centralizer univ = center M :=
Subset.antisymm (fun _ ha ↦ Semigroup.mem_center_iff.mpr fun b ↦ ha b (Set.mem_univ b)) fun _ ha b _ ↦
(ha.comm b).symm