  In this paper, we present a pricing mechanism that aligns incentives of
agents who exchange resources on a decentralized ledger with the goal of
maximizing transaction throughput. Subdividing a blockchain ledger into shards
promises to greatly increase transaction throughput with minimal loss of
security. However, the organization and type of the transactions also affects
the ledger's efficiency, which is increased by wallet agents transacting in a
single shard whenever possible while collectively distributing their
transactions uniformly across the available shards. Since there is no central
authority to enforce these properties, the only means of achieving them is to
design the system such that it is in agents' interest to act in a way that
benefits overall throughput. We show that our proposed pricing policy does
exactly this by inducing a potential game for the agents, where the potential
function relates directly to ledger throughput. Simulations demonstrate that
this policy leads to near-optimal throughput under a variety of conditions.
