
Briefing
The core research problem addresses the economic security of next-generation leaderless blockchain protocols, where multiple block producers concurrently contribute to block creation, which existing fee mechanisms fail to incentivize correctly. The foundational breakthrough is the introduction of the First-Price Auction with Equal Sharing (FPA-EQ) , a mechanism proven to satisfy the newly defined strongly BPIC (Block Producer Incentive Compatible) property by making the intended behavior a Pareto-dominant Nash equilibrium for all producers. This new theory establishes a necessary compromise in the mechanism design space, proving that while FPA-EQ secures a strong incentive alignment and a significant welfare fraction, no strongly BPIC mechanism can simultaneously achieve optimal welfare or be Dominant Strategy Incentive Compatible. The single most important implication is the provision of a rigorous, game-theoretic foundation for designing economically secure and scalable transaction fee markets for all future DAG-based and multi-proposer decentralized architectures.

Context
Prior to this work, the entire body of transaction fee mechanism literature, including sophisticated designs like EIP-1559, focused exclusively on leader-based protocols. In these traditional systems (like Bitcoin or Ethereum pre-Merge), a single entity ∞ the miner or validator ∞ possesses monopoly power over the contents of their block, simplifying the incentive problem to a user-to-leader auction. The emergence of high-throughput, leaderless consensus protocols, such as those built on Directed Acyclic Graphs (DAGs), introduced a critical, unmodeled challenge ∞ the “game within the game” of coordinating the economic behavior of multiple, simultaneously proposing block producers.

Analysis
The paper’s core mechanism, FPA-EQ, fundamentally differs from previous approaches by explicitly modeling the interaction between block producers as an extensive-form, multi-stage game. The new primitive is the strongly BPIC property, which is a powerful condition for block producer incentive compatibility. FPA-EQ operates by having users submit bids in a first-price auction format, but instead of the entire fee going to a single leader, the revenue from the included transactions is equally shared among all contributing block producers. This equal sharing component is the key logical shift, as it transforms the multi-proposer competition from a zero-sum race to maximize individual block revenue into a cooperative mechanism where the Nash equilibrium is aligned with the protocol’s intended allocation rule, securing the system’s economic integrity.

Parameters
- Strongly BPIC Property ∞ The condition that following the intended allocation rule is a Nash equilibrium for block producers that Pareto dominates all other Nash equilibria.
- Welfare Guarantee ∞ 63.2% fraction of the maximum-possible expected welfare guaranteed at equilibrium by the FPA-EQ mechanism.

Outlook
This research opens a new avenue for mechanism design research, shifting the focus from single-leader optimization to multi-proposer coordination and aggregation. In the next 3-5 years, this theoretical foundation will be critical for the practical deployment and economic stability of high-throughput DAG-based protocols, like those used by major Layer 1 and Layer 2 solutions. Future work will focus on extending the strongly BPIC property to account for collusion resistance and incorporating MEV mitigation strategies within the multi-proposer game model to ensure long-term, fair transaction ordering.

Verdict
This work provides the essential game-theoretic framework required to establish economic security and incentive alignment for the next generation of leaderless, high-concurrency decentralized systems.
