On an incoming edge, Deficit will denote the difference between the number of messages received and the number of signals sent in reply.
Then it sends enough signals to ensure that the deficit is zero on each incoming edge.
Send signals on all incoming edges except the first edge.
(Each node will send signals which reduces the deficit on each incoming edge to zero.)
It is assumed that edges can be labelled with empty strings to terminate strings where necessary and that the root has no incoming edge.
For directed graphs, each vertex has at most one incoming edge.
Now, for each node other than the root, mark an (arbitrarily chosen) incoming edge of lowest cost.
Now, suppose that in the SRT of , the (unique) incoming edge at is .
The second process increases the probability of high-degree nodes' receiving new incoming edges.
The fourth parameter incoming defines set of incoming edges when the node is added to the graph.