Join of two graphs admits a nowhere-zero 3 -flow

Saieed Akbari; Maryam Aliakbarpour; Naryam Ghanbari; Emisa Nategh; Hossein Shahmohamad

Czechoslovak Mathematical Journal (2014)

  • Volume: 64, Issue: 2, page 433-446
  • ISSN: 0011-4642

Abstract

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Let G be a graph, and λ the smallest integer for which G has a nowhere-zero λ -flow, i.e., an integer λ for which G admits a nowhere-zero λ -flow, but it does not admit a ( λ - 1 ) -flow. We denote the minimum flow number of G by Λ ( G ) . In this paper we show that if G and H are two arbitrary graphs and G has no isolated vertex, then Λ ( G H ) 3 except two cases: (i) One of the graphs G and H is K 2 and the other is 1 -regular. (ii) H = K 1 and G is a graph with at least one isolated vertex or a component whose every block is an odd cycle. Among other results, we prove that for every two graphs G and H with at least 4 vertices, Λ ( G H ) 3 .

How to cite

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Akbari, Saieed, et al. "Join of two graphs admits a nowhere-zero $3$-flow." Czechoslovak Mathematical Journal 64.2 (2014): 433-446. <http://eudml.org/doc/262039>.

@article{Akbari2014,
abstract = {Let $G$ be a graph, and $\lambda $ the smallest integer for which $G$ has a nowhere-zero $\lambda $-flow, i.e., an integer $\lambda $ for which $G$ admits a nowhere-zero $\lambda $-flow, but it does not admit a $(\lambda -1)$-flow. We denote the minimum flow number of $G$ by $\Lambda (G)$. In this paper we show that if $G$ and $H$ are two arbitrary graphs and $G$ has no isolated vertex, then $\Lambda (G \vee H) \le 3$ except two cases: (i) One of the graphs $G$ and $H$ is $K_2$ and the other is $1$-regular. (ii) $H = K_1$ and $G$ is a graph with at least one isolated vertex or a component whose every block is an odd cycle. Among other results, we prove that for every two graphs $G$ and $H$ with at least $4$ vertices, $\Lambda (G \vee H) \le 3$.},
author = {Akbari, Saieed, Aliakbarpour, Maryam, Ghanbari, Naryam, Nategh, Emisa, Shahmohamad, Hossein},
journal = {Czechoslovak Mathematical Journal},
keywords = {nowhere-zero $\lambda $-flow; minimum nowhere-zero flow number; join of two graphs; nowhere-zero $\lambda $-flow; minimum nowhere-zero flow number; join of two graphs},
language = {eng},
number = {2},
pages = {433-446},
publisher = {Institute of Mathematics, Academy of Sciences of the Czech Republic},
title = {Join of two graphs admits a nowhere-zero $3$-flow},
url = {http://eudml.org/doc/262039},
volume = {64},
year = {2014},
}

TY - JOUR
AU - Akbari, Saieed
AU - Aliakbarpour, Maryam
AU - Ghanbari, Naryam
AU - Nategh, Emisa
AU - Shahmohamad, Hossein
TI - Join of two graphs admits a nowhere-zero $3$-flow
JO - Czechoslovak Mathematical Journal
PY - 2014
PB - Institute of Mathematics, Academy of Sciences of the Czech Republic
VL - 64
IS - 2
SP - 433
EP - 446
AB - Let $G$ be a graph, and $\lambda $ the smallest integer for which $G$ has a nowhere-zero $\lambda $-flow, i.e., an integer $\lambda $ for which $G$ admits a nowhere-zero $\lambda $-flow, but it does not admit a $(\lambda -1)$-flow. We denote the minimum flow number of $G$ by $\Lambda (G)$. In this paper we show that if $G$ and $H$ are two arbitrary graphs and $G$ has no isolated vertex, then $\Lambda (G \vee H) \le 3$ except two cases: (i) One of the graphs $G$ and $H$ is $K_2$ and the other is $1$-regular. (ii) $H = K_1$ and $G$ is a graph with at least one isolated vertex or a component whose every block is an odd cycle. Among other results, we prove that for every two graphs $G$ and $H$ with at least $4$ vertices, $\Lambda (G \vee H) \le 3$.
LA - eng
KW - nowhere-zero $\lambda $-flow; minimum nowhere-zero flow number; join of two graphs; nowhere-zero $\lambda $-flow; minimum nowhere-zero flow number; join of two graphs
UR - http://eudml.org/doc/262039
ER -

References

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  7. Tutte, W. T., 10.4153/CJM-1954-010-9, Can. J. Math. 6 (1954), 80-91. (1954) Zbl0055.17101MR0061366DOI10.4153/CJM-1954-010-9
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  9. West, D. B., Introduction to Graph Theory, Prentice Hall, Upper Saddle River (1996). (1996) Zbl0845.05001MR1367739

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