Three-dimensional normal pseudomanifolds with relatively few edges
نویسندگان
چکیده
منابع مشابه
Three-Dimensional Pseudomanifolds on Eight Vertices
A normal pseudomanifold is a pseudomanifold in which the links of simplices are also pseudomanifolds. So, a normal 2-pseudomanifold triangulates a connected closed 2-manifold. But, normal d-pseudomanifolds form a broader class than triangulations of connected closed dmanifolds for d ≥ 3. Here, we classify all the 8-vertex neighbourly normal 3-pseudomanifolds. This gives a classification of all ...
متن کاملOn Normal Stratified Pseudomanifolds
Any pl-stratified pseudomanifod can be normalized preserving its intersection homology. In this paper we extend this result for any topological stratified pseudomanifold and for a family of perversities which is larger than usual. Our construction is functorial. We also give a detailed description of the normalizer’s stratification in terms of the initial stratified pseudomanifold.
متن کاملColoring uniform hypergraphs with few edges
A hypergraph is b-simple if no two distinct edges share more than b vertices. Let m(r, t, g) denote the minimum number of edges in an r-uniform non-t-colorable hypergraph of girth at least g. Erdős and Lovász proved that m(r, t, 3) ≥ t 2(r−2) 16r(r − 1)2 and m(r, t, g) ≤ 4 · 20g−1r3g−5t(g−1)(r+1). A result of Szabó improves the lower bound by a factor of r2− for sufficiently large r. We improve...
متن کاملColour-critical graphs with few edges
A graph G is called k-critical if G is k-chromatic but every proper subgraph of G has chromatic number at most k 1. In this paper the following result is proved. If G is a k-critical graph (k>~4) on n vertices, then 21E(G)I>(k 1)n ÷ ((k 3)/(k 2 3))n + k 4 where n>~k + 2 and n ~ 2 k 1. This improves earlier bounds established by Dirac (1957) and Gallai (1963). (~) 1998 Elsevier Science B.V. All ...
متن کاملNon-existence of 6-dimensional pseudomanifolds with complementarity
In a previous paper ([10]) the second author showed that if M is a pseudomanifold with complementarity other than the 6-vertex real projective plane and the 9-vertex complex projective plane, then M must have dimension ≥ 6, and in case of equality M must have exactly 12 vertices. In this paper we prove that such a 6-dimensional pseudomanifold does not exist. On the way to proving our main resul...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Advances in Mathematics
سال: 2020
ISSN: 0001-8708
DOI: 10.1016/j.aim.2020.107035