Different from Basic-LeadSum, every message on repost tree T , no matter detected as a leader or a follower, participates in ranking process of Soft-LeadSum.
in the random walk, visitor wanders on a complete graph G = (V, E ) whose vertex set V is identical to repost tree T , and E = {(u, v)|u ∈ V, v ∈ V, and u = v} represents the edge set.