scholarly journals Clique Trees of Infinite Locally Finite Chordal Graphs

10.37236/3928 ◽  
2018 ◽  
Vol 25 (2) ◽  
Author(s):  
Christoph Hofer-Temmel ◽  
Florian Lehner
Keyword(s):  
Chordal Graph ◽  
Chordal Graphs ◽  
Locally Finite ◽  
Clique Trees ◽  
Clique Tree

We investigate clique trees of infinite locally finite chordal graphs. Our main contribution is a bijection between the set of clique trees and the product of local finite families of finite trees. Even more, the edges of a clique tree are in bijection with the edges of the corresponding collection of finite trees. This allows us to enumerate the clique trees of a chordal graph and extend various classic characterisations of clique trees to the infinite setting. 

Clique Partitions of Chordal Graphs

1993 ◽  
Vol 2 (4) ◽  
pp. 409-415 ◽  
Author(s):  
Paul Erdős ◽  
Edward T. Ordman ◽  
Yechezkel Zalcstein
Keyword(s):  
Chordal Graph ◽  
Chordal Graphs ◽  
Split Graph ◽  
Threshold Graph

To partition the edges of a chordal graph on n vertices into cliques may require as many as n2/6 cliques; there is an example requiring this many, which is also a threshold graph and a split graph. It is unknown whether this many cliques will always suffice. We are able to show that (1 − c)n2/4 cliques will suffice for some c > 0.

Bonferroni-Type Inequalities via Chordal Graphs

2002 ◽  
Vol 11 (4) ◽  
pp. 349-351 ◽  
Author(s):  
KLAUS DOHMEN
Keyword(s):  
Type Inequality ◽  
Chordal Graph ◽  
Chordal Graphs ◽  
Finite Collection ◽  
Selection Of

Let {Av}v∈V be a finite collection of events and G = (V, E) be a chordal graph. Our main result – the chordal graph sieve – is a Bonferroni-type inequality where the selection of intersections in the estimates is determined by a chordal graph G. It interpolates between Boole's inequality (G empty) and the sieve formula (G complete). By varying G, several inequalities both well-known and new are obtained in a concise and unified way.

scholarly journals An introduction to chordal graphs and clique trees

1992 ◽  
Author(s):  
J.R.S. Blair ◽  
B.W. Peyton
Keyword(s):  
Chordal Graphs ◽  
Clique Trees

scholarly journals A $\beta$ Invariant for Greedoids and Antimatroids

10.37236/1298 ◽  
1997 ◽  
Vol 4 (1) ◽  
Author(s):  
Gary Gordon
Keyword(s):  
Chordal Graph ◽  
Chordal Graphs ◽  
Combinatorial Interpretations

We extend Crapo's $\beta $ invariant from matroids to greedoids, concentrating especially on antimatroids. Several familiar expansions for $\beta (G)$ have greedoid analogs. We give combinatorial interpretations for $\beta (G)$ for simplicial shelling antimatroids associated with chordal graphs. When $G$ is this antimatroid and $b(G)$ is the number of blocks of the chordal graph $G$, we prove $\beta (G)=1-b(G)$.

scholarly journals A clique tree algorithm for partitioning a chordal graph into transitive subgraphs

1995 ◽  
Vol 223-224 ◽  
pp. 553-588 ◽  
Author(s):  
Barry W. Peyton ◽  
Alex Pothen ◽  
Xiaoqing Yuan
Keyword(s):  
Chordal Graph ◽  
Tree Algorithm ◽  
Clique Tree

scholarly journals An Edge-Signed Generalization of Chordal Graphs, Free Multiplicities on Braid Arrangements, and Their Characterizations

2009 ◽  
Vol DMTCS Proceedings vol. AK,... (Proceedings) ◽  
Author(s):  
Takuro Abe ◽  
Koji Nuida ◽  
Yasuhide Numata
Keyword(s):  
Special Kind ◽  
Chordal Graph ◽  
Hyperplane Arrangements ◽  
Chordal Graphs ◽  
Nous Proposons ◽  
Signed Graphs ◽  
International Audience ◽  
Perfect Elimination Ordering

International audience In this article, we propose a generalization of the notion of chordal graphs to signed graphs, which is based on the existence of a perfect elimination ordering for a chordal graph. We give a special kind of filtrations of the generalized chordal graphs, and show a characterization of those graphs. Moreover, we also describe a relation between signed graphs and a certain class of multiarrangements of hyperplanes, and show a characterization of free multiarrangements in that class in terms of the generalized chordal graphs, which generalizes a well-known result by Stanley on free hyperplane arrangements. Finally, we give a remark on a relation of our results with a recent conjecture by Athanasiadis on freeness characterization for another class of hyperplane arrangements. Dans cet article, nous proposons une généralisation de la notion des graphes triangulés à graphes signés, qui est basée sur l'existence d'un ordre d'élimination simplicial à un graphe triangulé. Nous donnons un genre spécial de filtrations des graphes triangulés généralisés, et montrons une caractérisation de ces graphes. De plus, nous décrivons aussi une relation entre graphes signés et une certaine classe de multicompositions d'hyperplans, et montrons une caractérisation de multicompositions libres dans cette classe en termes des graphes triangulés généralisés, qui généralise un résultat célèbre de Stanley sur compositions libres d'hyperplans. Finalement, nous donnons une remarque sur une relation de nos résultats avec une conjecture récente d'Athanasiadis sur une caractérisation du freeness d'une autre classe de compositions d'hyperplans.

scholarly journals A Note on Independence Complexes of Chordal Graphs and Dismantling

10.37236/5571 ◽  
2017 ◽  
Vol 24 (2) ◽  
Author(s):  
Michał Adamaszek
Keyword(s):  
Chordal Graph ◽  
Chordal Graphs ◽  
Homotopy Equivalent ◽  
Tree Models ◽  
Independence Complex

We show that the independence complex of a chordal graph is contractible if and only if this complex is dismantlable (strong collapsible) and it is homotopy equivalent to a sphere if and only if its core is a cross-polytopal sphere. The proof uses the properties of tree models of chordal graphs.

scholarly journals Clique tree generalization and new subclasses of chordal graphs

2002 ◽  
Vol 117 (1-3) ◽  
pp. 109-131 ◽  
Author(s):  
P.Sreenivasa Kumar ◽  
C.E.Veni Madhavan
Keyword(s):  
Chordal Graphs ◽  
Clique Tree
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