Intriguing Sets in Partial Quadrangles

被引:8
作者
Bamberg, John [1 ]
De Clerck, Frank [2 ]
Durante, Nicola [3 ]
机构
[1] Univ Western Australia, Sch Math & Stat, Crawley, WA 6009, Australia
[2] Univ Ghent, Dept Math, B-9000 Ghent, Belgium
[3] Univ Naples Federico II, Dipartimento Matemat & Applicaz, I-80125 Naples, Italy
关键词
partial quadrangle; strongly regular graph; association scheme; TIGHT SETS; M-OVOIDS; HEMISYSTEMS;
D O I
10.1002/jcd.20269
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
The point-line geometry known as a partial quadrangle (introduced by Cameron in 1975) has the property that for every point/line non-incident pair (P, l), there is at most one line through P concurrent with l. So in particular, the well-studied objects known as generalized quadrangles are each partial quadrangles. An intriguing set of a generalized quadrangle is a set of points which induces an equitable partition of size two of the underlying strongly regular graph. We extend the theory of intriguing sets of generalized quadrangles by Bamberg, Law and Penttila to partial quadrangles, which gives insight into the structure of hemisystems and other intriguing sets of generalized quadrangles. (C) 2010 Wiley Periodicals, Inc. J Combin Designs 19: 217-245, 2011
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页码:217 / 245
页数:29
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