- What Is the Centralizer of an Element in Group Theory?
by DogmathicIn group theory, the centralizer of an element tells us which elements of the group commute with it. For an element aa in… Read more: What Is the Centralizer of an Element in Group Theory? - Why Is the Intersection of Two Subgroups Always a Subgroup?
by DogmathicWhy does this always work? The subgroup test gives us a short proof.