  Payment channel networks use off-chain transactions to provide virtually
arbitrary transaction rates. In this paper, we provide a new perspective on
payment channels and consider them as a flow network. We propose an extended
push-relabel algorithm to find payment flows in a payment channel network. Our
algorithm enables a distributed and concurrent execution without violating
capacity constraints. To this end, we introduce the concept of capacity
locking. We prove that flows are valid and present first results.
