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A Nearest-Neighbor Hard-Core Model on a Penrose Graph

Mathematical Physics 2026-04-24 v1 math.MP Probability

Abstract

We prove that the maximal graph-density of an independent set in a Penrose P3 tiling considered as a planar non-directed graph is equal to (57255)/20.54915(57 - 25 \sqrt{5})/2 \approx 0.54915 despite the fact that the graph is bipartite. Accordingly, the extreme Gibbs measure of the nearest-neighbor hard core particle model on this graph is unique for sufficiently large values of the particle activity. This invalidates a natural expectation to observe the coexistence of even and odd phases.

Cite

@article{arxiv.2604.21086,
  title  = {A Nearest-Neighbor Hard-Core Model on a Penrose Graph},
  author = {A. Mazel and I. Stuhl and Y. Suhov},
  journal= {arXiv preprint arXiv:2604.21086},
  year   = {2026}
}
R2 v1 2026-07-01T12:31:29.994Z