共查询到20条相似文献,搜索用时 0 毫秒
1.
A t-cover of a quadric
is a set C of t-dimensional subspaces contained in
such that every point of
is contained in at least one element of C.We consider (n – 1)-covers of the hyperbolic quadric Q
+(2n + 1, q). We show that such a cover must have at least q
n + 1 + 2q + 1 elements, give an example of this size for even q and describe what covers of this size should look like. 相似文献
2.
3.
Hazel Everett Sylvain Lazard Giuseppe Liotta Stephen Wismath 《Discrete and Computational Geometry》2010,43(2):272-288
This paper shows that any planar graph with n vertices can be point-set embedded with at most one bend per edge on a universal set of n points in the plane. An implication of this result is that any number of planar graphs admit a simultaneous embedding without mapping with at most one bend per edge. 相似文献
4.
Periodica Mathematica Hungarica - For any integer l and any positive integer n, let $$ \sigma _{l}(n)=\sum _{d\mid n}d^{l}$$ . In 1936, Erd?s proved that the set of positive integers n with... 相似文献
5.
6.
We give conditions allowing an intrinsic isometry on a dense subset to be extended to an isometry of the whole set. This enables us to find examples of (n-1)-dimensional sets rigid in
n
. 相似文献
7.
Shangzhi Li 《Geometriae Dedicata》1990,33(3):241-250
All the overgroups of SU(n, K, f) or (n, K, Q) in GL(n, K) are determined, for arbitrary division rings K and arbitrary forms f or Q with positive Witt indices. 相似文献
8.
Nacima Memić 《P-Adic Numbers, Ultrametric Analysis, and Applications》2018,10(3):209-221
We describe dynamical systems associated to (1 ? 1)-rational functions on the field of p-adic numbers.We focus on sets of minimality of such systems. 相似文献
9.
Motivated by the identity t (K n+2; 1, –1) = t (K n ; 2, –1), where t(G; x, y) is the Tutte polynomial of a graph G, we search for graphs G having the property that there is a pair of vertices u, v such that t(G; 1, –1) = t(G – {u, v}; 2, –1). Our main result gives a sufficient condition for a graph to have this property; moreover, it describes the graphs for which the property still holds when each vertex is replaced by a clique or a coclique of arbitrary order. In particular, we show that the property holds for the class of threshold graphs, a well-studied class of perfect graphs. 相似文献
10.
In this paper k-sets of type (a, b) with respect to hyperplanes are constructed in finite projective spaces using powers of Singer cycles. These are then used to construct further examples of sets of type (a, b) using various disjoint sets. The parameters of the associated strongly regular graphs are also calculated. The construction technique is then related to work of Foulser and Kallaher classifying rank three subgroups of AL(1, p
R). It is shown that the sets of type (a, b) arising from the Foulser and Kallaher construction in the case of projective spaces are isomorphic to some of those constructed in the present paper. 相似文献
11.
QIN Da-wei SHEN Da-peng 《数学季刊》2007,(1)
It is shown that the Ramsey number r(K_(2,s 1),K_(1,n))(?)n sn~(1/2) (s 3)/2 o(1) for large n,and r(K_(2,s 1),K_(1,n))∈{((q-1)~2/s) 1,((q-1)~2/s) 2},where n=((q-1)~2/s)-q 2 and q is a prime power such that s|(q-1). 相似文献
12.
In this article we study minimal1-blocking sets in finite projective spaces PG(n,q),n 3. We prove that in PG(n,q
2),q = p
h
, p prime, p > 3,h 1, the second smallest minimal 1-blockingsets are the second smallest minimal blocking sets, w.r.t.lines, in a plane of PG(n,q
2). We also study minimal1-blocking sets in PG(n,q
3), n 3, q = p
h, p prime, p > 3,q 5, and prove that the minimal 1-blockingsets of cardinality at most q
3 + q
2 + q + 1 are eithera minimal blocking set in a plane or a subgeometry PG(3,q). 相似文献
14.
设$(M,\,T)$是一个带有光滑对合$T$的光滑闭流形,
$T$在$M$上的不动点集为 $F=\{x\,|\,T(x)=x,\,x\in M\}$,
则$F$为$M$的闭子流形的不交并. 本文证明了: 当$F=P(2m,\,2l+1)\sqcup
P(2m,\,2n+1)$时,其中$n>l\geq m,\,m\neq1,\,3$, $(M,\,T)$协边于零. 相似文献
15.
k-smoothPointsofm(Ω,R)WangShushi(王漱石)(DepartmentofMathematics,HuzhouNormalCollege,Huzhou,Zhejiang,313000)Abstract:Inthispoper... 相似文献
16.
Zhengxin Chen 《代数通讯》2013,41(8):3297-3324
17.
Annali di Matematica Pura ed Applicata (1923 -) - In a recent work on Euler-type formulae for even Dirichlet beta values, i.e., $$\beta {(2n)}$$ , I have derived an exact closed-form expression for... 相似文献
18.
Lynn Margaret Batten Kris Coolsaet Anne Penfold Street 《Designs, Codes and Cryptography》1997,10(3):309-314
The existence of blocking sets in (, {2, 4}, 1)-designs is examined. We show that for 0, 3, 5, 6, 7, 8, 9, 11 (mod 12>), blocking sets cannot exist. We prove that for each 1, 2, 4 (mod 12) there is a (, {2, 4}, 1)-design with a blocking set with three possible exceptions. The case 10 (mod 12) is still open; we consider the first four values of in this situation. 相似文献
19.
In this paper, k-blocking sets in PG(n, q), being of Rédei type, are investigated. A standard method to construct Rédei type k-blocking sets in PG(n, q) is to construct a cone having as base a Rédei type k-blocking set in a subspace of PG(n, q). But also other Rédei type k-blocking sets in PG(n, q), which are not cones, exist. We give in this article a condition on the parameters of a Rédei type k-blocking set of PG(n, q = p
h
), p a prime power, which guarantees that the Rédei type k-blocking set is a cone. This condition is sharp. We also show that small Rédei type k-blocking sets are linear. 相似文献
20.
A combinatorial proof that the number of points of the space \(\overline {{M_{0,n}}} \left( {{F_q}} \right)\) satisfies the recurrent formula for the Poincaré polynomials of the space \(\overline {{M_{0,n}}} \left( \mathbb{C} \right)\) is obtained. 相似文献