Show HN: Formally verified 3D CSG: Trust 93 lines spec, not 1000 lines AI code (github.com)

A groundbreaking project has introduced the first formally verified implementation of a 3D constructive solid geometry (CSG) operation, specifically mesh intersection, using Lean 4. This implementation allows reviewers to validate its correctness with just 93 lines of formal specifications, sidestepping the complexities of over 1,000 lines of AI-generated code. The Lean checker autonomously verifies over 60,000 lines of Lean proofs, eliminating the need for human inspection and enabling a high level of trust in the resulting kernel. The approach prioritizes correctness over performance, yielding slower intersection times compared to state-of-the-art algorithms, but sets a new standard in establishing reliability in AI-assisted coding. The significance of this development lies in its promise of trustworthiness in AI-generated code, which has traditionally been viewed with skepticism due to potential hidden bugs and errors. By decoupling the formal specification from the intricate implementation, the project demonstrates a practical pathway for using AI while ensuring rigorous correctness guarantees. The Lean system’s ability to define and prove properties of mesh solids, such as well-formedness, illustrates its potential to transform how geometrical computations are handled in the AI/ML domain, paving the way for more robust and reliable software development methodologies.