Assume is the optimal propagation path from the propagation source node v 1 to the node v t that leads to the highest confidence of v t , which means that c * Since v 1 is the source node whose timestamp is initially labeled and its confidence is 1, the inequality c A (v 1 ) < c * (v 1 ) cannot hold.
the assumption that c A (v t ) < c * (v t ) cannot be satisfied.