共查询到19条相似文献,搜索用时 78 毫秒
1.
韩广国 《高校应用数学学报(A辑)》2007,22(4):483-490
分类自同构群的基柱为李型单群E8(q)的区传递2-(v,k,1)设计,得到如下定理:设D为一个2-(v,k,1)设计,G≤Aut(D)是区传递、点本原但非旗传递的.若q〉24√(krk-kr+1)f(这里kr=(k,v-1),q=p^f,p是素数,f是正整数),则Soc(G)≌/E8(q). 相似文献
2.
AnneDelndtsheer在[1]中证明了:如果G在2-(v,k,1)设计上线本原,且k<30,则G点本原,本文将k范围扩大到了k≤40。 相似文献
3.
分类自同构群为射影辛群PSpn(q)的区传递2-(v,k,1)设计,得到如下定理:设D为一个2-(v,k,1)设计,G≤Aut(D)是区传递,点本原但非旗传递的.若q为偶数且n≥14,则GPSpn(q). 相似文献
4.
若$\cal D$为一个非平凡旗传递点本原对称$(v,k,4)$设计, 其基柱为${\rm PSL}_n(q)$且$G\leq {\rm Aut}(\cal D)$. 那么, $\cal D$ 必为$2$-$(15,8,4)$设计且${\rm Soc}(G)={\rm PSL}_2(9)$. 相似文献
5.
讨论自同构群是酉群PSU(3,q2)(q=2^l)的区-本原的2-(v,k,1)设计,首先证明了它必是点-本原的,然后确定了这种类型的设计,即它只能为2-(q3 1,q 1,1)设计。 相似文献
6.
受旗传递2-(v,k,3)对称设计和非对称2-(v,k,2)设计有关分类结果的启发,本论文继续研究旗传递非对称2-(v,k,3)设计.文章利用置换群的理论和组合设计的数量性质,借助计算机代数软件Gap和Magma,完全分类了自同构群G旗传递点本原,且基柱Soc(G)为交错群An(n≥5)的非对称2-(v,k,3)设计,证明了此类设计只能是唯一的2-(5,3,3)设计,且G=A_5或S_5. 相似文献
7.
讨论自同构群是酉群 PSU(3 ,q2 ) (q=2 l)的区 -本原的 2 -(v,k,1 )设计 .首先证明了它必是点 -本原的 ,然后确定了这种类型的设计 ,即它只能为 2 -(q3+1 ,q+1 ,1 )设计 相似文献
8.
设D是一个2-(v,k,1)设计,G是D的自同构群.Delandtsheer证明了如果G是区本原的,且D不是射影平面,则G是几乎单群,即存在一个非交换单群T,使得T≤G≤Aut(T).本文证明了T不同构于单群3D4(q),这是区本原设计分类工作的一个不可缺少的组成部分. 相似文献
9.
设$D$是一个非平凡的对称$(v,k,\lambda)$设计, $G$是$D$的一个自同构群.本文证明了如果$G$以二维典型群PSL$(2,q)$作为基柱且在$D$上的作用是旗传递和点本原的,那么设计$D$的参数只能为$(7, 3, 1)$, $(7, 4, 2)$, $(11, 5, 2)$, $(11, 6, 3)$或$(15, 8, 4)$. 相似文献
10.
11.
Let
be a 2-(v,k,1) design, and let G be a group of automorphisms of
. We show that if G is block primitive, then G does not admit a Ree group
as its socle. 相似文献
12.
Eugenia O’Reilly-Regueiro 《Designs, Codes and Cryptography》2010,56(1):61-63
It has been shown that if a (v, k, λ)-symmetric design with λ ≤ 3 admits a flag-transitive automorphism group G which acts primitively on points, then G must be of affine or almost simple type. Here we extend the result to λ = 4. 相似文献
13.
In (k, n) visual cryptographic schemes (VCS), a secret image is encrypted into n pages of cipher text, each printed on a transparency sheet, which are distributed among n participants. The image can be visually decoded if any k(≥2) of these sheets are stacked on top of one another, while this is not possible by stacking any k − 1 or fewer sheets. We employ a Kronecker algebra to obtain necessary and sufficient conditions for the existence of a (k, n) VCS with a prior specification of relative contrasts that quantify the clarity of the recovered image. The connection of
these conditions with an L
1-norm formulation as well as a convenient linear programming formulation is explored. These are employed to settle certain
conjectures on contrast optimal VCS for the cases k = 4 and 5. Furthermore, for k = 3, we show how block designs can be used to construct VCS which achieve optimality with respect to the average and minimum
relative contrasts but require much smaller pixel expansions than the existing ones. 相似文献
14.
A graph G is called an (n,k)-graph if κ(G-S)=n-|S| for any S ? V(G) with |S| ≤ k, where ?(G) denotes the connectivity of G. Mader conjectured that for k ≥ 3 the graph K2k+2?(1-factor) is the unique (2k, k)-graph. Kriesell has settled two special cases for k = 3,4. We prove the conjecture for the general case k ≥ 5. 相似文献
15.
The following results are proved. In Theorem 1, it is stated that there exist both finitely presented and not finitely presented
2-generated nonfree groups which are k-free-like for any k ⩾ 2. In Theorem 2, it is claimed that every nonvirtually cyclic (resp., noncyclic and torsion-free) hyperbolic m-generated group is k-free-like for every k ⩾ m + 1 (resp., k ⩾ m). Finally, Theorem 3 asserts that there exists a 2-generated periodic group G which is k-free-like for every k ⩾ 3.
Supported by NSF (grant Nos. DMS 0455881 and DMS-0700811). (A. Yu. Olshanskii, M. V. Sapir)
Supported by RFBR project No. 08-01-00573. (A. Yu. Olshanskii)
Supported by BSF grant (USA–Israel). (M. V. Sapir)
Translated from Algebra i Logika, Vol. 48, No. 2, pp. 245–257, March–April, 2009. 相似文献
16.
A proper incidentor coloring is called a (k, l)-coloring if the difference between the colors of the final and initial incidentors ranges between k and l. In the list variant, the extra restriction is added: the color of each incidentor must belong to the set of admissible colors of the arc. In order to make this restriction reasonable we assume that the set of admissible colors for each arc is an integer interval. The minimum length of the interval that guarantees the existence of a list incidentor (k, l)-coloring is called a list incidentor (k, l)-chromatic number. Some bounds for the list incidentor (k, l)-chromatic number are proved for multigraphs of degree 2 and 4. 相似文献
17.
We prove that if k is a positive integer and d is a positive integer such that the product of any two distinct elements of the set {k + 1, 4k, 9k + 3, d} increased by 1 is a perfect square, then d = 144k
3 + 192k
2 + 76k + 8.
相似文献
18.
In this paper, we give the eigenvalues of the manifold Sp(n)/U(n). We prove that an eigenvalue λ
s
(f
2, f
2, …, f
n
) of the Lie group Sp(n), corresponding to the representation with label (f
1, f
2, ..., f
n
), is an eigenvalue of the manifold Sp(n)/U(n), if and only if f
1, f
2, …, f
n
are all even. 相似文献
19.
Let k, n, and r be positive integers with k < n and \({r \leq \lfloor \frac{n}{k} \rfloor}\). We determine the facets of the r-stable n, k-hypersimplex. As a result, it turns out that the r-stable n, k-hypersimplex has exactly 2n facets for every \({r < \lfloor \frac{n}{k} \rfloor}\). We then utilize the equations of the facets to study when the r-stable hypersimplex is Gorenstein. For every k > 0 we identify an infinite collection of Gorenstein r-stable hypersimplices, consequently expanding the collection of r-stable hypersimplices known to have unimodal Ehrhart \({\delta}\)-vectors. 相似文献