Like Nano, every user maintains their own blockchain. That's where the similarities end though. What's interesting about this is it solves the ledger bloat issue, and can process 20000TPS, and is low latency, without requiring consensus via PoW or PoS. This would be a radical departure from Nano, but given the recent spam attacks, I'd believe this would give us a lot more headroom.
edit: another interesting paper that cites the previous: https://research.fb.com/wp-content/uploads/2020/10/FastPay-High-Performance-Byzantine-Fault-Tolerant-Settlement.pdf
edit 2: seems this is for permissioned blockchains...? But in appendix a, it mentions how to add / remove replicas, so not sure if this is a problem.