Title
There is no McLaughlin geometry
Abstract
We determine that there is no partial geometry G with parameters (s,t,α)=(4,27,2). The existence of such a geometry has been a challenging open problem of interest to researchers for almost 40 years. The particular interest in G is due to the fact that it would have the exceptional McLaughlin graph as its point graph. Our proof makes extensive use of symmetry and high-performance distributed computing, and details of our techniques and checks are provided. One outcome of our work is to show that a pseudogeometric strongly regular graph achieving equality in the Krein bound need not be the point graph of any partial geometry.
Year
DOI
Venue
2018
10.1016/j.jcta.2017.10.004
Journal of Combinatorial Theory, Series A
Keywords
Field
DocType
Partial geometry,Pseudogeometric graph,McLaughlin geometry,McLaughlin graph,Krein bound,Backtrack search
Partial geometry,Discrete mathematics,Graph,Combinatorics,Strongly regular graph,Open problem,Geometry,Mathematics
Journal
Volume
ISSN
Citations 
155
0097-3165
0
PageRank 
References 
Authors
0.34
0
2
Name
Order
Citations
PageRank
Patric R. J. Östergård160970.61
Leonard H. Soicher24810.38