Formally verified 3D CSG: Trust 93 lines spec, not 1000 lines AI code
To my knowledge, this is the first formally verified implementation of a 3D constructive solid geometry (CSG) operation: mesh intersection, implemented in Lean 4 and verified against a concise specification that pins down the surface of the resulting mesh exactly and guarantees practical well-formedness conditions on the triangulation. This project is also an experiment in avoiding having to trust AI-generated code. A human reviewer only needs to read 93 lines of formal specification and run the Lean checker to certify the correctness of the kernel, skipping the intricate 1000+ lines of…
Formally verified 3D CSG: Trust 93 lines spec, not 1000 lines AI code launched on July 28, 2026 with 115 votes, #338 of 24,623 launches that month and more than 95% of that year's launches.
In plain words
This is a formally verified implementation of 3D mesh intersection using Lean 4, designed to eliminate the need to trust AI-generated code. Reviewers need only examine a 93-line specification and run the Lean checker to verify correctness, while the system's 1000+ lines of implementation and 60,000+ lines of proofs are automatically generated and guaranteed correct at compile time. It serves developers and researchers who require cryptographically assured correctness in computational geometry operations.
written from the facts on this page · September 2026
From the sources
Formally verified 3D mesh intersection - trust 93 lines of spec, not 1000+ lines of AI-written code - schildep/verified-3d-mesh-intersection
In the maker’s words, at launch
To my knowledge, this is the first formally verified implementation of a 3D constructive solid geometry (CSG) operation: mesh intersection, implemented in Lean 4 and verified against a concise specification that pins down the surface of the resulting mesh exactly and guarantees practical well-formedness conditions on…
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