Give a formal proof that graph isomorphism is an equivalence relation

5 points How many unique graphs are there on n = 3 vertices? Draw all such graphs on n = 3 vertices and indicate which, if any, are isomorphic to each other 10 points

How many unique graphs are there on n = 4 vertices? Draw all graphs that are not isomorphic to each other (hint: there are 11 such graphs); indicate how many graphs on n = 4 vertices are isomorphic to each one of these.

3. In general, for an undirected graph with n vertices, how many unique graphs are there?