Abstract
We show that there are simple 4-dimensional polytopes with n vertices such that all separators of the graph have size at least Ω(n/log n). This establishes a strong form of a claim by Thurston, for which the construction and proof had been lost.
We construct the polytopes by cutting off the vertices and then the edges of a particular type of neighborly cubical polytopes. The graphs of simple polytopes thus obtained are 4-regular; they contain 3-regular “cube-connected cycle graphs” as minors of spanning subgraphs.
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The first author was funded by DFG through the Berlin Mathematical School. Research by the second author was supported by the DFG Collaborative Research Center TRR 109 “Discretization in Geometry and Dynamics.”
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Loiskekoski, L., Ziegler, G.M. Simple polytopes without small separators, II: Thurston’s bound. Isr. J. Math. 228, 293–303 (2018). https://doi.org/10.1007/s11856-018-1764-3
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DOI: https://doi.org/10.1007/s11856-018-1764-3