... cd -index of [u, v], and it is denoted byψu,v(c, d). Noticethat the complete cd -index of [u, v] is an encoding of the distribution of the descent sets of each path ∆ in the Bruhat graph of ... terms of degree k − 1 (correspondingto paths of length k), then it also has terms of degree k + 1 (corresponding to paths of length k + 2).There are some specializations of the complete cd -index ... face poset of a regular cell decomposition of a sphere (see [3], [11]).For w ∈ W , we define the negative set of w, denoted by N(w), to be the set of reflections that shorten the length of w, i.e.,...