Minimum proper interval graphs : Notas de Matemática, 52

A graph G is a proper interval graph if there exists a mapping r from V(G) to the class of closed intervals of the real line with the properties that for distinct vertices v and w we have r(n) ∩ r(w) 7^ 0 if and only if v and w are adjacent and neither of the intervals r(v), r(w) contain the other....

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Autores principales: Gutiérrez, Marisa, Oubiña, Lía
Formato: Publicacion seriada
Lenguaje:Inglés
Publicado: 1993
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/170313
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spelling I19-R120-10915-1703132024-09-18T04:11:11Z http://sedici.unlp.edu.ar/handle/10915/170313 Minimum proper interval graphs : Notas de Matemática, 52 Gutiérrez, Marisa Oubiña, Lía 1993 2024-09-17T17:49:35Z en Matemática A graph G is a proper interval graph if there exists a mapping r from V(G) to the class of closed intervals of the real line with the properties that for distinct vertices v and w we have r(n) ∩ r(w) 7^ 0 if and only if v and w are adjacent and neither of the intervals r(v), r(w) contain the other. We prove that for every proper interval graph G, | V(C7)| > 2c(G) — c(7C(Gi)), where c(G) is the number of cliques of G and Λ’((7) is the clique graph of G. If the equality is verified we call G a minimum proper interval graph. The main result is that the restriction to the class of minimum proper interval graphs of clique mapping G —> A(G) is a bijection (up to isomorphism) onto the class of proper interval graphs. We find the greatest clique-closed class Σ (i.e. Α(Σ) = Σ) contained in the union of the class of connected minimum proper interval graphs and the class of complete graphs . We enumerate the minimun proper interval graphs with n vertices. Material digitalizado en SEDICI gracias a la colaboración de la Biblioteca del Departamento de Matemática de la Facultad de Ciencias Exactas (UNLP). Facultad de Ciencias Exactas Publicacion seriada Publicacion seriada http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Matemática
spellingShingle Matemática
Gutiérrez, Marisa
Oubiña, Lía
Minimum proper interval graphs : Notas de Matemática, 52
topic_facet Matemática
description A graph G is a proper interval graph if there exists a mapping r from V(G) to the class of closed intervals of the real line with the properties that for distinct vertices v and w we have r(n) ∩ r(w) 7^ 0 if and only if v and w are adjacent and neither of the intervals r(v), r(w) contain the other. We prove that for every proper interval graph G, | V(C7)| > 2c(G) — c(7C(Gi)), where c(G) is the number of cliques of G and Λ’((7) is the clique graph of G. If the equality is verified we call G a minimum proper interval graph. The main result is that the restriction to the class of minimum proper interval graphs of clique mapping G —> A(G) is a bijection (up to isomorphism) onto the class of proper interval graphs. We find the greatest clique-closed class Σ (i.e. Α(Σ) = Σ) contained in the union of the class of connected minimum proper interval graphs and the class of complete graphs . We enumerate the minimun proper interval graphs with n vertices.
format Publicacion seriada
Publicacion seriada
author Gutiérrez, Marisa
Oubiña, Lía
author_facet Gutiérrez, Marisa
Oubiña, Lía
author_sort Gutiérrez, Marisa
title Minimum proper interval graphs : Notas de Matemática, 52
title_short Minimum proper interval graphs : Notas de Matemática, 52
title_full Minimum proper interval graphs : Notas de Matemática, 52
title_fullStr Minimum proper interval graphs : Notas de Matemática, 52
title_full_unstemmed Minimum proper interval graphs : Notas de Matemática, 52
title_sort minimum proper interval graphs : notas de matemática, 52
publishDate 1993
url http://sedici.unlp.edu.ar/handle/10915/170313
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