Preliminaries A path from node n to n is defined as a sequence of nodes m,n,n...,nk such that n is the parent of n for 1≤Kk The length of this path is the number of edges on the path,namely k1.There is a path of length zero from every node to itself.Notice that in a tree there is exactly one path from the root to each node.Preliminaries ◼ A path from node n1 to nk is defined as a sequence of nodes n1 , n2 , n3…, nk such that ni is the parent of ni+1 for 1i<k. ◼ The length of this path is the number of edges on the path, namely k-1. There is a path of length zero from every node to itself. Notice that in a tree there is exactly one path from the root to each node