DendrogramMat(A,t,s):: Mat, Rat, Int --> List

Inputs an n\times n symmetric matrix A over the rationals, a rational t \ge 0 and an integer s \ge 1. A list [v_1, \ldots, v_{t+1}] is returned with each v_k a list of positive integers. Let t_k = (k-1)s. Let G(A,t_k) denote the graph with vertices 1, \ldots, n and with distinct vertices i and j connected by an edge when the (i,j) entry of A is \le t_k. The i-th path component of G(A,t_k) is included in the v_k[i]-th path component of G(A,t_{k+1}). This defines the integer vector v_k. The vector v_k has length equal to the number of path components of G(A,t_k).