- Fix n ≥ 3 to be an integer. How many graphs are there that aresub-graphs of Kn (assume that all nodes are different and included in the sub-graph)?
Thanks Brothers !
There are non-empty subsets of vertices.
If we chose a subset of vertices and include any edge between any two of them, then that is the number of sub-graphs.
Now some authors do not allow single vertex sub-graphs.
In that case we use the number