  The Bitcoin protocol is a significant milestone in the history of money.
However, its adoption is currently constrained by the transaction limits of the
system. As the chief problem of blockchain technology, the scaling issue has
attracted many valuable solutions both on-chain and off-chain. In this paper,
our goal is to explore the notion of unspent transaction outputs (UTXOs) to
propose an augmented Bitcoin protocol that can scale gracefully. Our proposal
aims to increase the transaction throughput by partitioning the UTXO space and
splitting the blockchain. In addition, a new type of Bitcoin node is introduced
to preserve the capability to run validating nodes in low-bandwidth
environments, despite the increased transaction throughput.
