当前位置: X-MOL 学术Graphs Comb. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Group Divisible Designs with Block Size Four and Type $$g^u b^1 (gu/2)^1$$ g u b 1 ( g u / 2 ) 1
Graphs and Combinatorics ( IF 0.7 ) Pub Date : 2020-07-23 , DOI: 10.1007/s00373-020-02213-5
Anthony D. Forbes

We discuss group divisible designs with block size four and type \(g^u b^1 (gu/2)^1\), where \(u = 5\), 6 and 7. For integers a and b, we prove the following. (i) A 4-GDD of type \((4a)^5 b^1 (10a)^1\) exists if and only if \(a \ge 1\), \(b \equiv a\) (mod 3) and \(4a \le b \le 10a\). (ii) A 4-GDD of type \((6a+3)^6 b^1 (18a+9)^1\) exists if and only if \(a \ge 0\), \(b \equiv 3\) (mod 6) and \(6a+3 \le b \le 18a + 9\). (iii) A 4-GDD of type \((6a)^6 b^1 (18a)^1\) exists if and only if \(a \ge 1\), \(b \equiv 0\) (mod 3) and \(6a \le b \le 18a\). (iv) A 4-GDD of type \((12a)^7 b^1 (42a)^1\) exists if and only if \(a \ge 1\), \(b \equiv 0\) (mod 3) and \(12a \le b \le 42a\), except possibly for \(12a \in \{120, 180, 240, 360, 420, 720, 840\}\), \(24a< b < 42a\), for \(12a \in \{144, 1008\}\), \(30a< b < 42a\), and for \(12a \in \{168, 252, 336, 504, 1512\}\), \(36a< b < 42a\).



中文翻译:

块大小为4且类型为$$ g ^ ub ^ 1(gu / 2)^ 1 $$ gub 1(gu / 2)1的组可分割设计

我们讨论块大小为4且类型为\(g ^ ub ^ 1(gu / 2)^ 1 \)的组可分割设计,其中\(u = 5 \),6和7。对于整数ab,我们证明了以下。(i)当且仅当\ {a \ ge 1 \)\(b \ equiv a \)(mod才存在类型为\((4a)^ 5 b ^ 1(10a)^ 1 \)的4-GDD 3)和\(4a \ le b \ le 10a \)。(ii)当且仅当\(a \ ge 0 \)\(b \ equiv 3时,存在类型为\((6a + 3)^ 6 b ^ 1(18a + 9)^ 1 \)的4-GDD \)(mod 6)和\(6a + 3 \ le b \ le 18a + 9 \)。(iii)当且仅当存在一个类型为\((6a)^ 6 b ^ 1(18a)^ 1 \)的4-GDD\(a \ ge 1 \)\(b \ equiv 0 \)(mod 3)和\(6a \ le b \ le 18a \)。(iv)当且仅当\ {a \ ge 1 \)\(b \ equiv 0 \)(mod才存在类型为\((12a)^ 7 b ^ 1(42a)^ 1 \)的4-GDD 3)和\(12a \ le b \ le 42a \),除了\ {12a \ in \ {120,180,240,360,420,720,840 \} \)可能的除外\(24a <b <42a \)\(12a \ in \ {144,1008 \} \)\(30a <b <42a \)\(12a \ in \ {168,252,336,504,1512 \} \ )\(36A <b <42A \)

更新日期:2020-07-23
down
wechat
bug