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arXiv · 2409.00846

Undecidability of Translational Tiling of the 4-dimensional Space with a Set of 4 Polyhypercubes

Chao Yang·Zhujun Zhang
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Abstract

Recently, Greenfeld and Tao disprove the conjecture that translational tilings of a single tile can always be periodic [Ann. Math. 200(2024), 301-363]. In another paper [to appear in J. Eur. Math. Soc.], they also show that if the dimension $n$ is part of the input, the translational tiling for subsets of $\mathbb{Z}^n$ with one tile is undecidable. These two results are very strong pieces of evidence for the conjecture that translational tiling of $\mathbb{Z}^n$ with a monotile is undecidable, for some fixed $n$. This paper shows that translational tiling of the $3$-dimensional space with a set of $5$ polycubes is undecidable. By introducing a technique that lifts a set of polycubes and its tiling from $3$-dimensional space to $4$-dimensional space, we manage to show that translational tiling of the $4$-dimensional space with a set of $4$ tiles is undecidable. This is a step towards the attempt to settle the conjecture of the undecidability of translational tiling of the $n$-dimensional space with a monotile, for some fixed $n$.

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Chao Yang, Zhujun Zhang. 2024-09-01. Undecidability of Translational Tiling of the 4-dimensional Space with a Set of 4 Polyhypercubes. https://doi.org/10.1007/s11425-024-2365-2

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