1. Let S = {s1,s2,...,sn}. How many functions are there with domain S and target Z2? Of those functions, how many are one-to-one? How many are onto?
2. Draw all non-isomorphic simple graphs with four vertices. (There are 11.) Verify that the handshaking lemma holds for each graph.
3. Do it again for graphs with five vertices. How many graphs did you find?