Here are 2 graphs, G1 and G2. I am given the following: Graph G1 is given as: V(G1) = {1, 2, . . . , 7}, E(G1) = {< x, y > | x < y>, x<= x+2}.
Graph G2 is given as: V(G2) = {1, 2, . . . , 9}, E(G2) = {< x, y > | x divides y, x < y>}. Then I am asked to find and draw G1∩G2 and G1∪G2. What I don't understand is the vertices of the given graph G2 as shown below are less than 9 so why are they given as reaching 9? And what does x divides y or x < y>, x<= x+2 mean? Any explanation is appreciated. Thanks in advance!