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OP-00023 Open

Closed form for the top of the boat–star tiling spectrum

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Let $\Gamma_\bigstar$ be the tile graph of the boat–star tiling: Penrose's pentagon tiling P1, generated by the six-tile substitution of Grünbaum and Shephard (Definition 3.1 of the source), with one vertex per tile and tiles adjacent when they share an edge. Let $\Sigma_\bigstar$ be the spectrum of its graph Laplacian $\Delta = D - A$. Its bottom, $\min\Sigma_\bigstar = 0$, follows from elementary arguments; its top is not as easy to compute.

Problem. Can $\max\Sigma_\bigstar$ be computed in closed form?

Source: Damanik, Embree, Fillman and Mei, Question 8.3 in “Discontinuities of the integrated density of states for Laplacians associated with Penrose and Ammann–Beenker tilings”, Experimental Mathematics 33 (2024); arXiv:2209.01443.

Imported from arxiv.org/abs/2209.01443.

Classification

Primary
SP — Spectral Theory
Secondary
DS, MP
Keywords
aperiodic order, graph Laplacian, Penrose tiling, spectral edges
Literature checked
Oct. 1, 2026 by clemens-admin

References

@article{damanik2024,
  author = {Damanik, David and Embree, Mark and Fillman, Jake and Mei, May},
  title = {Discontinuities of the integrated density of states for {L}aplacians associated with {P}enrose and {A}mmann--{B}eenker tilings},
  journal = {Experimental Mathematics},
  volume = {33},
  number = {4},
  pages = {588--610},
  year = {2024},
  doi = {10.1080/10586458.2023.2206589},
  eprint = {2209.01443},
  archivePrefix = {arXiv}
}

@book{grunbaum1987,
  author = {Gr{\"u}nbaum, Branko and Shephard, G. C.},
  title = {Tilings and Patterns},
  publisher = {W. H. Freeman and Company},
  address = {New York},
  year = {1987}
}

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OP-00023, "Closed form for the top of the boat–star tiling spectrum", clopen.solutions.