A Non-Shellable 3-Sphere
نویسندگان
چکیده
منابع مشابه
Non-Shellable Drawings of Kn with Few Crossings
In the early 60s, Harary and Hill conjectured H(n) := 1 4b2 cbn−1 2 cbn−2 2 cbn−3 2 c to be the minimum number of crossings among all drawings of the complete graph Kn. It has recently been shown that this conjecture holds for so-called shellable drawings of Kn. For n ≥ 11 odd, we construct a non-shellable family of drawings of Kn with exactly H(n) crossings. In particular, every edge in our dr...
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Suppose a group G acts properly on a simplicial complex Γ . Let l be the number of G-invariant vertices, and p1,p2, . . . , pm be the sizes of the G-orbits having size greater than 1. Then Γ must be a subcomplex of Λ = Δl−1 ∗ ∂Δp1−1 ∗ · · · ∗ ∂Δpm−1. A result of Novik gives necessary conditions on the face numbers of Cohen–Macaulay subcomplexes of Λ. We show that these conditions are also suffi...
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ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 1985
ISSN: 0195-6698
DOI: 10.1016/s0195-6698(85)80026-3