The problem studied in this article is the directed Kirkman packing,the resolvable directed packing which requires all blocks to be of size three except that,each resolution class should contain either one block of si...The problem studied in this article is the directed Kirkman packing,the resolvable directed packing which requires all blocks to be of size three except that,each resolution class should contain either one block of size two(when v≡2(mod 3)) or one block of size four (when v≡1 (mod 3)).A directed Kirkman packing design DKPD(v) is a resolvable directed packing of a v-set by the maximum possible number of resolution classes of this type.This article investigates the spectrum of DKPD(v) and it is found that it contains all positive integers v≥3 and v≠5,6.展开更多
In this paper, we introduce a new concept -- overlarge sets of generalized Kirkman systems （OLGKS）, research the relation between it and OLKTS, and obtain some new results for OLKTS. The main conclusion is： If ther...In this paper, we introduce a new concept -- overlarge sets of generalized Kirkman systems （OLGKS）, research the relation between it and OLKTS, and obtain some new results for OLKTS. The main conclusion is： If there exist both an OLKF（6^k） and a 3-OLGKS（6^k-1,4） for all k ∈{6,7,...,40}／{8,17,21,22,25,26}, then there exists an OLKTS（v） for any v ≡ 3 （mod 6）, v ≠ 21. As well, we obtain the following result： There exists an OLKTS（6u ＋ 3） for u = 2^2n-1 - 1, 7^n, 31^n, 127^n, 4^r25^s, where n ≥ 1,r＋s≥ 1.展开更多
In this paper, we investigate the intersection numbers of nearly Kirkman triple systems.JN[V] is the set of all integers k such that there is a pair of NKTS（v）s with a common uncovered collection of 2-subset interse...In this paper, we investigate the intersection numbers of nearly Kirkman triple systems.JN[V] is the set of all integers k such that there is a pair of NKTS（v）s with a common uncovered collection of 2-subset intersecting in k triples. It has been established that JN[v] = {0, 1,. v（v-2）/6-6,v（v-2）/6-4,v（v-2）/6} for any integers v = 0 （mod 6） and v ≥ 66. For v ≤ 60, there are 8 cases leftundecided.展开更多
It is proved in this paper that,for any given positive integer k≥2,there exists a constant v0=v0(k) such that for v≥v0,the necessary condition v=0 (mod k(k-)) for the existence of a nearly Kirkman system NKS (2,k,v)...It is proved in this paper that,for any given positive integer k≥2,there exists a constant v0=v0(k) such that for v≥v0,the necessary condition v=0 (mod k(k-)) for the existence of a nearly Kirkman system NKS (2,k,v) is also sufficient.Thus we have completely determined the asymptotic existence of NKS.展开更多
文摘The problem studied in this article is the directed Kirkman packing,the resolvable directed packing which requires all blocks to be of size three except that,each resolution class should contain either one block of size two(when v≡2(mod 3)) or one block of size four (when v≡1 (mod 3)).A directed Kirkman packing design DKPD(v) is a resolvable directed packing of a v-set by the maximum possible number of resolution classes of this type.This article investigates the spectrum of DKPD(v) and it is found that it contains all positive integers v≥3 and v≠5,6.
基金supported by NSFC Grant 10671055NSFHB A2007000230Foundation of Hebei Normal University L2004Y11, L2007B22
文摘In this paper, we introduce a new concept -- overlarge sets of generalized Kirkman systems （OLGKS）, research the relation between it and OLKTS, and obtain some new results for OLKTS. The main conclusion is： If there exist both an OLKF（6^k） and a 3-OLGKS（6^k-1,4） for all k ∈{6,7,...,40}／{8,17,21,22,25,26}, then there exists an OLKTS（v） for any v ≡ 3 （mod 6）, v ≠ 21. As well, we obtain the following result： There exists an OLKTS（6u ＋ 3） for u = 2^2n-1 - 1, 7^n, 31^n, 127^n, 4^r25^s, where n ≥ 1,r＋s≥ 1.
基金Supported by the Fundamental Research Funds for the Central Universities(Grant No.2014JBM121)National Natural Science Foundation of China(Grant Nos.11271042,11471032 and 11571034)
文摘In this paper, we investigate the intersection numbers of nearly Kirkman triple systems.JN[V] is the set of all integers k such that there is a pair of NKTS（v）s with a common uncovered collection of 2-subset intersecting in k triples. It has been established that JN[v] = {0, 1,. v（v-2）/6-6,v（v-2）/6-4,v（v-2）/6} for any integers v = 0 （mod 6） and v ≥ 66. For v ≤ 60, there are 8 cases leftundecided.
基金Project supported by the National Natural Sdence Foundation of China
文摘It is proved in this paper that,for any given positive integer k≥2,there exists a constant v0=v0(k) such that for v≥v0,the necessary condition v=0 (mod k(k-)) for the existence of a nearly Kirkman system NKS (2,k,v) is also sufficient.Thus we have completely determined the asymptotic existence of NKS.
