Typhon's Chimera Chains Chimera Chains generalize shared sequencers. They use a consensus based on Heterogeneous Paxos to simplify cross-blockchain atomic transactions for chains with overlapping trust models.
Distributed Systems Heterogeneous Paxos and Multi-Chain Atomic Commits Heterogeneous Paxos exploits the high intersection between validator sets of different blockchain to create a heterogeneous consensus protocol for atomic multi-chain transactions & extends the capabilities of IBC to allow for arbitrary communication between chains within an atomic transaction