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Difference between revisions of "Regular graph"

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(Start article: Regular graph)
 
 
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{{TEX|done}}{{MSC|05C99}}
 
{{TEX|done}}{{MSC|05C99}}
  
An unoriented [[graph]] in which each vertex has the same degree.
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An unoriented [[graph]] in which each vertex has the same degree.  If the common degree is $k$, the graph may be termed ''$k$-regular''.
  
 
A '''strongly regular graph''' is a regular graph in which any two adjacent vertices have the same number of neighbours in common, and any two non-adjacent vertices have the same number of neighbours in common.  The [[Graph complement|complement]] of a strongly regular graph is again strongly regular.
 
A '''strongly regular graph''' is a regular graph in which any two adjacent vertices have the same number of neighbours in common, and any two non-adjacent vertices have the same number of neighbours in common.  The [[Graph complement|complement]] of a strongly regular graph is again strongly regular.
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====References====
 
====References====
* Richard A Brualdi, Herbert J. Ryser, "Combinatorial matrix theory", Cambridge University Press (2014) ISBN 978-0-521-32265-2 {{ZBL|0746.05002}} {{ZBL|1286.05001}}
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* Richard A Brualdi, Herbert J. Ryser, "Combinatorial matrix theory", Cambridge University Press (2014) {{ISBN|978-0-521-32265-2}} {{ZBL|0746.05002}} {{ZBL|1286.05001}}
* Andries E. Brouwer, Arjeh M. Cohen, Arnold Neumaier, "Distance-regular graphs" Springer (1989) ISBN 3-642-74343-6 {{ZBL|0747.05073}}
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* Andries E. Brouwer, Arjeh M. Cohen, Arnold Neumaier, "Distance-regular graphs" Springer (1989) {{ISBN|3-642-74343-6}} {{ZBL|0747.05073}}

Latest revision as of 14:17, 12 November 2023

2020 Mathematics Subject Classification: Primary: 05C99 [MSN][ZBL]

An unoriented graph in which each vertex has the same degree. If the common degree is $k$, the graph may be termed $k$-regular.

A strongly regular graph is a regular graph in which any two adjacent vertices have the same number of neighbours in common, and any two non-adjacent vertices have the same number of neighbours in common. The complement of a strongly regular graph is again strongly regular.

A distance regular graph is one with the property that for any two vertices $x,y$ the number of vertices at distance $i$ from $x$ and $j$ from $y$ depends only on $i$, $j$ and the distance $d(x,y)$.

References

  • Richard A Brualdi, Herbert J. Ryser, "Combinatorial matrix theory", Cambridge University Press (2014) ISBN 978-0-521-32265-2 Zbl 0746.05002 Zbl 1286.05001
  • Andries E. Brouwer, Arjeh M. Cohen, Arnold Neumaier, "Distance-regular graphs" Springer (1989) ISBN 3-642-74343-6 Zbl 0747.05073
How to Cite This Entry:
Regular graph. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Regular_graph&oldid=51396