Citation

Durvasula, N. “The Monotone Priority System: Foundations of Contract-Specific Sequencing.” arXiv:2601.20783v1 [cs.DB] (28 Jan 2026). Columbia University & Ritual.

Core Contribution

An axiomatically justified way for smart-contract developers to impose sequencing constraints on the transactions that interact with them, balancing expressivity against block-building tractability. Developers set an integer global priority for each contract call, subject to the constraint that a call’s priority is no higher than any call it references; builders simply sequence transactions in priority order (high→low), breaking ties freely. The paper proves this is the unique system satisfying five independent axioms.

The Tension It Resolves

  • Arbitrary per-pair constraints → block building becomes a Boolean-satisfiability problem; a valid block may not even exist.
  • Status quo (no contract control) → tractable but developers have zero ordering power; a profit-maximizing builder decides winners.
  • The Monotone Priority System sits in the “sweet spot”: maximally expressive under a tractability definition, while keeping block building a simple priority sort.

Motivating Use Case

Decentralized order books: after a price shock, standing buy orders are stale; a race erupts between cancellations (market makers) and stale-fill arbitrageurs. Exchanges are widely believed to be better off prioritizing cancellations (protecting LPs). Contract-specific sequencing lets the order-book contract enforce “cancellations before fills” rather than leaving it to the builder. Some leading DEXs already do this ad hoc.

Connection to Wiki

See Also