Periodic orbit-closure conjecture for exact-cluster tilings

From papers

Let FZ2F\subseteq\mathbb{Z}^2 be an exact cluster with full affine span, and let TT be an FF-tiling. The orbit closure of TT is

Z2T=cl{vT:vZ2}.\overline{\mathbb{Z}^2\cdot T}=\operatorname{cl}\{v\cdot T:v\in\mathbb{Z}^2\}.

A tiling is 11-periodic if it has a nonzero period in Z2\mathbb{Z}^2.

Periodic orbit-closure conjecture. The orbit closure

Z2T\overline{\mathbb{Z}^2\cdot T}

contains a 11-periodic FF-tiling.

This conjecture would extend the expected link between low pattern complexity and periodicity to tilings by possibly non-convex windows. The paper states that its counterexample refutes this conjecture, so it is disproved.

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Sources & referencesView supporting material

Primary source

Abhishek Khetan, “A Counterexample to Nivat's Conjecture for a Non-Convex Window of Full Affine Span”, arXiv:2607.09830 (2026).

Additional references

3 papers in this index state this conjecture (2013–2026). The statement above is taken from the most recent of them; the others are arXiv:2507.12654, arXiv:1312.0386.

Solutions 0

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