Extensions of the transient analysis for random walks
The following cases are tractable by extended analysis:
-   Several random walks in parallel
    product formula for the probability that independent trials miss a node
-   Random walk without step back  (except for nodes of degree 1)
    increased state space for analysis: network edges instead of nodes,
         but the run time complexity is unchanged
-   Random walk followed by flooding on distance d after the last step
    extend absorbing state to the set of all neighbors up to distance d
-   Random walk search for replicated data on n nodes
    use a set of n absorbing states or
         assume a binomial distributed hit count based on single node search