Hacker News with Generative AI: Computational Geometry

Twenty Questions with a Random Liar (11011110.github.io)
I have another new arXiv preprint: “Computational geometry with probabilistically noisy primitive operations”, arXiv:2501.07707, with Mike Goodrich and his student Vinesh Sridhar. Many computational geometry algorithms are designed around the use of primitives, subroutines that access the coordinate data of the input and convert it into combinatorial information, with the assumption that all access to the input goes through these primitives.
Tiling with Three Polygons Is Undecidable (arxiv.org)
We prove that the following problem is co-RE-complete and thus undecidable: given three simple polygons, is there a tiling of the plane where every tile is an isometry of one of the three polygons (either allowing or forbidding reflections)? This result improves on the best previous construction which requires five polygons.