Results 101 to 110 of about 11,526 (190)
On the Maximum Estrada Index of 3-Uniform Linear Hypertrees
The Scientific World Journal, 2014 For a simple hypergraph H on n vertices, its Estrada index is defined as EE(H)=∑i=1neλi, where λ1,λ2,…,λn are the eigenvalues of its adjacency matrix. In this paper, we determine the unique 3-uniform linear hypertree with the maximum Estrada index.
Faxu Li +4 more
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Equitable Orientations of Sparse Uniform Hypergraphs
The Electronic Journal of Combinatorics, 2016 Caro, West, and Yuster (2011) studied how $r$-uniform hypergraphs can be oriented in such a way that (generalizations of) indegree and outdegree are as close to each other as can be hoped. They conjectured an existence result of such orientations for sparse hypergraphs, of which we present a proof.
Cohen, Nathann, Lochet, William
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Online Matching on 3-Uniform Hypergraphs
The online matching problem was introduced by Karp, Vazirani and Vazirani (STOC 1990) on bipartite graphs with vertex arrivals. It is well-known that the optimal competitive ratio is $1-1/e$ for both integral and fractional versions of the problem.
Sander Borst +2 more
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Maximizing Spectral Radii of Uniform Hypergraphs with Few Edges
Discussiones Mathematicae Graph Theory, 2016 In this paper we investigate the hypergraphs whose spectral radii attain the maximum among all uniform hypergraphs with given number of edges. In particular we characterize the hypergraph(s) with maximum spectral radius over all unicyclic hypergraphs ...
Fan Yi-Zheng +3 more
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Complement Reducible Uniform Hypergraphs
AxiomsWe investigate a generalization of complement reducible graphs, called co-graphs, for r-uniform hypergraphs. The operations of r-co-hypergraphs are the disjoint union of two given r-co-hypergraphs and the join operation, which inserts all hyperedges of ...
Frank Gurski, Jochen Rethmann
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Constructing and sampling partite, 3-uniform hypergraphs with given degree sequence.
PLoS ONEPartite, 3-uniform hypergraphs are 3-uniform hypergraphs in which each hyperedge contains exactly one point from each of the 3 disjoint vertex classes. We consider the degree sequence problem of partite, 3-uniform hypergraphs, that is, to decide if such ...
András Hubai +4 more
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Discrete Mathematics, 1986 \textit{D. Buset} [Discrete Math. 57, 297-299 (1985; Zbl 0587.05030)] determined for \(k=2\) the sets of all pairs (a,b) such that there exists a k-uniform (connected k-uniform) hypergraph whose automorphism group has exactly a orbits on the set of vertices and b orbits on the set of edges. The author extended this result for arbitrary natural k.
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Perfect matchings in 4-uniform hypergraphs
Journal of Combinatorial Theory, Series B, 2016 A perfect matching in a 4-uniform hypergraph is a subset of $\lfloor\frac{n}{4}\rfloor$ disjoint edges. We prove that if $H$ is a sufficiently large 4-uniform hypergraph on $n=4k$ vertices such that every vertex belongs to more than ${n-1\choose 3} - {3n/4 \choose 3}$ edges then $H$ contains a perfect matching.
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Chromatic Coefficients of Linear Uniform Hypergraphs
Journal of Combinatorial Theory, Series B, 1998 Formulae are given for the coefficients of the highest powers of \(\lambda\) in the chromatic polynomial \(P(H,\lambda)\) of a linear uniform \(h\)-hypergraph \(H\), thus generalizing the corresponding result of \textit{G. H. J. Meredith} for graphs [J. Comb. Theory, Ser. B 13, 14-17 (1972; Zbl 0218.05056)]. Some differences appear whenever (\(g= 3\), \
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Finding Set Extreme 3-Uniform Hypergraphs Cardinality through Second-Order Signatures
AxiomsThis paper continues the study of second-order signature properties—the characterization of the extreme 3-uniform hypergraph. Previously, bases were used to count extreme 3-uniform hypergraphs.
Evgeniya Egorova +3 more
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