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Group Divisible Designs with Block Size Four and Group Type for
Authors:Hengjia Wei  Gennian Ge
Affiliation:1. Department of Mathematics, Zhejiang University, Hangzhou, P. R. China;2. School of Mathematical Sciences, Capital Normal University, Beijing, P. R. China
Abstract:Nonuniform group divisible designs (GDDs) have been studied by numerous researchers for the past two decades due to their essential role in the constructions for other types of designs. In this paper, we investigate the existence problem of urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0005‐GDDs of type urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0006 for urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0007. First, we determine completely the spectrum of urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0008‐GDDs of types urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0009 and urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0010. Furthermore, for general cases, we show that for each urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0011 and urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0012, a urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0013‐GDD of type urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0014 exists if and only if urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0015, urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0016 and urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0017, except possibly for urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0018, urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0019 and urn:x-wiley:10638539:jcd21336:equation:jcd21336-math-0020.
Keywords:group divisible designs  double group divisible designs  incomplete group divisible designs AMS subject classifications: Primary 05B05
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