How can I find all non-isomorphic graphs with 2, 3 or 4 nodes, including not-connected ones?
I know that to graphs $G_1$ and $G_2$ are isomorphic, if there is a bijective depiction $f: V(G_1) \rightarrow V(G_2) $ so that $[x,y] \in E(G_1) \Leftrightarrow [f(x),f(y)] \in E(G_2)$.
How can I use this to solve the task?