Support for multiple units of account in Cycles

Develop mechanisms within the Cycles protocol to represent and optimize over obligation graphs that include multiple units of account and operate at different scales, enabling atomic multilateral settlement across heterogeneous denominational structures.

Background

The paper’s user flow description initially assumes a single unit of account to simplify graph construction and optimization. The authors note that real-world payment networks often involve multiple units of account across different scales, which complicates multilateral settlement and optimization.

They explicitly indicate this capability is deferred, highlighting the need to extend Cycles’ graph and solver to handle multi-unit obligations while maintaining privacy and atomicity. The mention of optimal currency areas underscores the economic considerations and potential criteria for partitioning or coupling units in practice.