Split clique graph complexity

A complete set of a graph G is a subset of vertices inducing a complete subgraph. A clique is a maximal complete set. Denote by C(G) the clique family of G. The clique graph of G, denoted by K(G), is the intersection graph of C(G). Say that G is a clique graph if there exists a graph H such that G=K...

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Detalles Bibliográficos
Autores principales: Alcón, Liliana Graciela, Faria, Luerbio, Figueiredo, C. M. H. de, Gutiérrez, Marisa
Formato: Articulo
Lenguaje:Inglés
Publicado: 2013
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84984
Aporte de:
id I19-R120-10915-84984
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Matemática
Clique graphs
Helly property
NP-complete
Split graphs
spellingShingle Ciencias Exactas
Matemática
Clique graphs
Helly property
NP-complete
Split graphs
Alcón, Liliana Graciela
Faria, Luerbio
Figueiredo, C. M. H. de
Gutiérrez, Marisa
Split clique graph complexity
topic_facet Ciencias Exactas
Matemática
Clique graphs
Helly property
NP-complete
Split graphs
description A complete set of a graph G is a subset of vertices inducing a complete subgraph. A clique is a maximal complete set. Denote by C(G) the clique family of G. The clique graph of G, denoted by K(G), is the intersection graph of C(G). Say that G is a clique graph if there exists a graph H such that G=K(H). The clique graph recognition problem, a long-standing open question posed in 1971, asks whether a given graph is a clique graph and it was recently proved to be NP-complete even for a graph G with maximum degree 14 and maximum clique size 12. Hence, if P ≠ NP, the study of graph classes where the problem can be proved to be polynomial, or of more restricted graph classes where the problem remains NP-complete is justified. We present a proof that given a split graph G=(V,E) with partition (K,S) for V, where K is a complete set and S is a stable set, deciding whether there is a graph H such that G is the clique graph of H is NP-complete. As a byproduct, we prove that determining whether a given set family admits a spanning family satisfying the Helly property is NP-complete. Our result is optimum in the sense that each vertex of the independent set of our split instance has degree at most 3, whereas when each vertex of the independent set has degree at most 2 the problem is polynomial, since it is reduced to the problem of checking whether the clique family of the graph satisfies the Helly property. Additionally, we show three split graph subclasses for which the problem is polynomially solvable: the subclass where each vertex of S has a private neighbor, the subclass where |S|≤3, and the subclass where |K|≤4.
format Articulo
Articulo
author Alcón, Liliana Graciela
Faria, Luerbio
Figueiredo, C. M. H. de
Gutiérrez, Marisa
author_facet Alcón, Liliana Graciela
Faria, Luerbio
Figueiredo, C. M. H. de
Gutiérrez, Marisa
author_sort Alcón, Liliana Graciela
title Split clique graph complexity
title_short Split clique graph complexity
title_full Split clique graph complexity
title_fullStr Split clique graph complexity
title_full_unstemmed Split clique graph complexity
title_sort split clique graph complexity
publishDate 2013
url http://sedici.unlp.edu.ar/handle/10915/84984
work_keys_str_mv AT alconlilianagraciela splitcliquegraphcomplexity
AT farialuerbio splitcliquegraphcomplexity
AT figueiredocmhde splitcliquegraphcomplexity
AT gutierrezmarisa splitcliquegraphcomplexity
bdutipo_str Repositorios
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