On Diregularity of Digraphs of Defect at Most Two

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

On Diregularity of Digraphs of Defect at Most Two

Popis výsledku v původním jazyce

It is easy to show that any digraph with out-degree at most d, diameter k at least 2 and order one or two less than Moore bound must have all vertices of out-degree d. However, establishing the regularity or otherwise of the in-degree of such a digraph is not easy. In this paper we prove that all digraphs of defect two are either diregular or almost diregular. Additionally, in the case of defect one we present a new, simpler and shorter, proof that a digraph of defect one must be diregular, and in the case of defect two and for d = 2 and k at least 3, we present an alternative proof that a digraph of defect two must be diregular.

Název v anglickém jazyce

On Diregularity of Digraphs of Defect at Most Two

Popis výsledku anglicky

It is easy to show that any digraph with out-degree at most d, diameter k at least 2 and order one or two less than Moore bound must have all vertices of out-degree d. However, establishing the regularity or otherwise of the in-degree of such a digraph is not easy. In this paper we prove that all digraphs of defect two are either diregular or almost diregular. Additionally, in the case of defect one we present a new, simpler and shorter, proof that a digraph of defect one must be diregular, and in the case of defect two and for d = 2 and k at least 3, we present an alternative proof that a digraph of defect two must be diregular.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BA - Obecná matematika

OECD FORD obor

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Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2009

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Combinatorial Mathematics and Combinatorial Computing

ISSN

0835-3026

e-ISSN

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Svazek periodika

71

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

CA - Kanada

Počet stran výsledku

18

Strana od-do

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Kód UT WoS článku

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EID výsledku v databázi Scopus

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