An l-regular graph, l 1, is a simple graph where all of its vertices have degree l. The union of two simple graphs G G U G2 = (V U V2, E1 U E2). = (V1, E1) and G2 = (V2, E2), is the simple graph Two subgraphs are disjoint, if they share no edges and no vertices. Show using induction or strong induction (whichever of the two you prefer) that any 2-regular graph is either a cycle or a union of two or more disjoint cycles.