The Monotone Priority System: Foundations of Contract-Specific Sequencing

TL;DR

This paper introduces the Monotone Priority System, a principled method for specifying transaction sequencing constraints in blockchain smart contracts using integer priorities, ensuring expressivity and tractability.

Contribution

It proposes a novel priority-based sequencing system for smart contracts that is axiomatically justified and balances expressivity with block production efficiency.

Findings

The system is the unique solution satisfying five independent axioms.

Contract developers can set priorities that influence transaction sequencing.

Block builders sequence transactions based on priority, ensuring fairness and consistency.

Abstract

Modern blockchain applications benefit from the ability to specify sequencing constraints on the transactions that interact with them. This paper proposes a principled and axiomatically justified way of adding sequencing constraints on smart contract function calls that balances expressivity with the tractability of block production. Specifically, we propose a system in which contract developers are allowed to set an integer global priority for each of their calls, so long as that the call's chosen priority is no higher than the priority of any of its referenced calls. Block builders must then simply sequence transactions in priority order (from high to low priority), breaking ties however they would like. We show that this system is the unique system that satisfies five independent axioms.