6. let g be a simple graph with n vertices and m edges. (a) how many edges does the complement g have? a simple graph is called self-complementary if it is isomorphic to its complement graph. (b) show that if g is self-complementary, then the number of vertices of g is either a multiple of 4, or one plus a multiple of 4. (hint: use (a) to derive an equation involving the number of vertices.)