EconCSLib uses Lean 4 and AI to verify computational economics proofs

EconCSLib is a new Lean 4 library developed by Xiaohui Bei, Jiajun Ma, Zhan Jing, Hongfei Fu, and Zhihao Gavin Tang, designed to bring machine-checkable formalization to computational economics. Inspired by the success of mathlib, the library aims to provide reusable definitions and theorems for game theory, mechanism design, social choice, and related fields. It serves both as infrastructure for researchers and as a case study for AI-assisted formalization, where interactive theorem provers and AI-based tools collaborate to turn mathematical statements into verified artifacts. The library also plans to host machine-checked open problems and formalize contemporary research papers, making rigorous verification accessible to economists.

Beyond its infrastructure role, EconCSLib leverages recent progress in AI-assisted programming and theorem proving to make large-scale formalization more practical. Accepted to the EC'26 Workshop on AI-Driven Research in EconCS, the paper discusses design principles, lessons learned, and future directions for integrating AI with formal verification in economics. By enabling trusted, machine-checked proofs for complex economic models, EconCSLib could help reduce errors in theoretical results and accelerate collaboration between AI researchers and economists.