A construction of small regular bipartite graphs of girth 8

Let q be a prime a power and k an integer such that 3 ≤ k ≤ q. In this paper we present a method using Latin squares to construct adjacency matrices of k-regular bipartite graphs of girth 8 on 2(kq2 -- q) vertices. Some of these graphs have the smallest number of vertices among the known regular graphs with girth 8.

[1]  E. Bannai,et al.  On finite Moore graphs , 1973 .

[2]  Felix Lazebnik,et al.  General properties of some families of graphs defined by systems of equations , 2001, J. Graph Theory.

[3]  Juan José Montellano-Ballesteros,et al.  On upper bounds and connectivity of cages , 2007, Australas. J Comb..

[4]  Dragan Marusic,et al.  The 10-cages and derived configurations , 2004, Discret. Math..

[5]  Brendan D. McKay,et al.  The Smallest Cubic Graphs of Girth Nine , 1995, Combinatorics, Probability and Computing.

[6]  M. O'Keefe,et al.  The smallest graph of girth 6 and valency 7 , 1981, J. Graph Theory.

[7]  András Gács,et al.  On geometric constructions of (k, g)-graphs , 2008, Contributions Discret. Math..

[8]  Richard M. Wilson,et al.  A course in combinatorics , 1992 .

[9]  Felix Lazebnik,et al.  New upper bounds on the order of cages , 1996, Electron. J. Comb..

[10]  H. Sachs,et al.  Regukre Graphen gegebener Taillenweite mit minimaler Knotenzahl , 1963 .

[11]  M. O’KEEFE,et al.  A smallest graph of girth 10 and valency 3 , 1980, J. Comb. Theory, Ser. B.

[12]  A. Barlotti,et al.  Combinatorics of Finite Geometries , 1975 .

[13]  Derek Allan Holton,et al.  The Petersen graph , 1993, Australian mathematical society lecture series.

[14]  C. T. Benson Minimal Regular Graphs of Girths Eight and Twelve , 1966, Canadian Journal of Mathematics.

[15]  Norman Biggs,et al.  Constructions for Cubic Graphs with Large Girth , 1998, Electron. J. Comb..

[16]  Walter Feit,et al.  The nonexistence of certain generalized polygons , 1964 .

[17]  Pak-Ken Wong,et al.  Cages - a survey , 1982, J. Graph Theory.

[18]  Felix Lazebnik,et al.  New Constructions of Bipartite Graphs on m, n Vertices with Many Edges and Without Small Cycles , 1994, J. Comb. Theory, Ser. B.

[19]  Markus Meringer,et al.  Fast generation of regular graphs and construction of cages , 1999, J. Graph Theory.

[20]  G. Exoo,et al.  Dynamic Cage Survey , 2011 .

[21]  W. T. Tutte A family of cubical graphs , 1947, Mathematical Proceedings of the Cambridge Philosophical Society.

[22]  P. K. Wong A REGULAR GRAPH OF GIRTH 6 AND VALENCY 11 , 1986 .

[23]  Zoltán Füredi,et al.  Graphs of Prescribed Girth and Bi-Degree , 1995, J. Comb. Theory, Ser. B.

[24]  Geoffrey Exoo A Simple Method for Constructing Small Cubic Graphs of Girths 14, 15, and 16 , 1996, Electron. J. Comb..

[25]  Gordon F. Royle,et al.  Algebraic Graph Theory , 2001, Graduate texts in mathematics.