Expectation of recursion in tree

96 Views Asked by At

Suppose I have a connected graph with $n$ vertices and $n-1$ edges, that is in form of a tree. Now, I will add the number of vertices in the tree and uniformly randomly select a vertex. I break the graph at this selected vertex, deleting the vertex and the edges connected to it. Now, I again repeat the same thing at all of the left components (sub-trees) until I am left with one vertex for which the answer is inherently $1$. What will be the expectation of the sum obtained by adding the number of vertices recursively in such a problem?