共查询到20条相似文献,搜索用时 15 毫秒
1.
T. G. Ostrom 《Aequationes Mathematicae》1977,15(2-3):121-133
2.
In this paper we introduce and analyze the notion of self-dual
k-sets of type (m, n).
We show that in a non-square order projective space such sets exist
only if the dimension is odd. We prove that, in a projective space of odd dimension
and order q, self-dual
k-sets of type (m, n), with
, are of elliptic and hyperbolic
type, respectively. As a corollary we obtain a new characterization of the
non-singular elliptic and hyperbolic quadrics. 相似文献
3.
The problem of classifying finite projective planes
of order n with an automorphism group G and a point orbit
on which G acts two-transitively is investigated in considerable detail, under the assumption that
has length at last n. Combining old and new results a rather satisfying classification is obtained, even though some cases for orbit lengths n and n + 1 remain unsolved. 相似文献
4.
Two non desarguesian flag transitive planes of order 34 whose Kernel is GF(3) are constructed. These planes are distinct from the planes of the same order contained in the class constructed by Narayana Rao M. L. (Proceedings of American Mathematical Society 39 (1973) 51–56) and Ebert, G.L. and Baker, R. (Enumeration of two dimensional Flag-Transitive planes, Algebras, Groups and Geometries 3 (1985) 248–257). The Flag Transitive group modulo the scalar collineations of these planes is generated by two elements and is of order 328. 相似文献
5.
G. Eric Moorhouse 《Geometriae Dedicata》1989,31(1):63-88
Let Π be a projective plane of order n admitting a collineation group G≅PSL(2, q) for some prime power q. It is well known for n=q that Π must be Desarguesian. We show that if n<q then only finitely many cases may occur for П, all of which are Desarguesian. We obtain some information in case n=q
2 with q odd, notably that G acts irreducibly on П for q≠3, 5, 9.
The material herein was presented to the University of Toronto in partial fulfillment of the requirements for the degree of
Doctor of Philosophy. The author is grateful to Professor Chat Y. Ho, presently at the University of Florida, for guidance
in this research. 相似文献
6.
Mikhail Tkachenko 《Journal of Pure and Applied Algebra》2010,214(7):1103-1109
We show that every Abelian group G with r0(G)=|G|=|G|ω admits a pseudocompact Hausdorff topological group topology T such that the space (G,T) is Fréchet-Urysohn. We also show that a bounded torsion Abelian group G of exponent n admits a pseudocompact Hausdorff topological group topology making G a Fréchet-Urysohn space if for every prime divisor p of n and every integer k≥0, the Ulm-Kaplansky invariant fp,k of G satisfies (fp,k)ω=fp,k provided that fp,k is infinite and fp,k>fp,i for each i>k.Our approach is based on an appropriate dense embedding of a group G into a Σ-product of circle groups or finite cyclic groups. 相似文献
7.
We show that in $\operatorname{PG}(4,2)$ there exist octets $\mathcal{P}
_{8}=\{\pi_{1},\,\ldots\,,\pi_{8}\}$ of planes such that the 28
intersections $\pi_{i}\cap\pi_{j}$ are distinct points. Such
conclaves (see [6]) $\mathcal{P}_{8}$ of planes
in $\operatorname{PG}(4,2)$ are shown to be in bijective correspondence
with those planes $P$ in $\operatorname{PG}(9,2)$ which are external to
the Grassmannian $\mathcal{G}_{1,4,2}$ and which belong to the orbit
$\operatorname{orb}(2\gamma)$ (see [4]). The fact
that, under the action of $\operatorname{GL}(5,2),$ the stabilizer
groups $\mathcal{G}_{\mathcal{P}_{8}}$ and $\mathcal{G}_{P}$ both have
the structure $2^{3}:(7:3)$ is thus illuminated. Starting out from a
regulus-free partial spread $\mathcal{S}_{8}$ in
$\operatorname{PG}(4,2)$ we also give a construction of a conclave of
planes $P\in\operatorname{orb}(2\gamma)\subset\operatorname{PG}(9,2).$ 相似文献
8.
9.
This paper is a contribution to the study of non-symmetric 2-designs admitting a flag-transitive automorphism group. We prove that if \(\mathcal {D}\) is a non-trivial non-symmetric 2-\((v, k, \lambda )\) design with \((r,\lambda ) = 1\) and \(G=PSL(2,q)\) acts flag-transitively on \(\mathcal {D}\), then up to isomorphism \(\mathcal {D}\) is a unique Witt-Bose-Shrikhande space, a unique 2-(6, 3, 2) design, a unique 2-(8, 4, 3) design, a unique 2-(10, 6, 5) design, or a unique 2-(28, 7, 2) design. 相似文献
10.
Let H(B) denote the space of all holomorphic functions on the unit ball B of Cn. Let φ be a holomorphic self-map of B and g ∈ H(B) such that g(0) = 0. In this paper, we investigate the boundedness and compactness of the generalized composition operator
11.
《组合设计杂志》2018,26(11):540-546
We use the connection between positive definite functions and the character table of the symmetric group S6 to give a short new proof of the nonexistence of a finite projective plane of order 6. For higher orders, like 10 and 12, the method seems to be inconclusive as of now, but could be a basis of further research. 相似文献
12.
Journal of Geometry - 相似文献
13.
Let p be an odd prime number. We describe the Whitehead group of all extra-special and almost extra-special p-groups. For this we compute, for any finite p-group P, the subgroup of , in terms of a genetic basis of P. We also introduce a deflation map , for a normal subgroup N of P, and show that it is always surjective. Along the way, we give a new proof of the result describing the structure of , when P is an elementary abelian p-group. 相似文献
14.
Every group is the automorphism group of a rank-3 extension of a rank-3 Dowling geometry.Partially supported by The George Washington University UFF grant.Partially supported by the National Security Agency under grant MDA904-91-H-0030. 相似文献
15.
The Riordan group consisting of Riordan matrices shows up naturally in a variety of combinatorial settings. In this paper, we define a q-Riordan matrix to be a q -analogue of the (exponential) Riordan matrix by using the Eulerian generating functions of the form ∑n?0fnzn/n!q. We first prove that the set of q-Riordan matrices forms a loop (a quasigroup with an identity element) and find its loop structures. Next, it is shown that q-Riordan matrices associated to the counting functions may be applied to the enumeration problem on set partitions by block inversions. This notion leads us to find q-analogues of the composition formula and the exponential formula, respectively. 相似文献
16.
Luca Esposito 《Journal of Differential Equations》2004,204(1):5-55
We prove regularity theorems for minimizers of integral functionals of the Calculus of Variations
17.
18.
Aart Blokhuis 《Combinatorica》1994,14(1):111-114
We show that the size of a non-trivial blocking set in the Desarguesian projective planePG(2,p), wherep is prime, is at least 3(p+1)/2. This settles a 25 year old conjecture of J. di Paola. 相似文献
19.
20.
ZhouShenglin 《高校应用数学学报(英文版)》2002,17(1):99-104
It is proved that if D be a 2-(v,k,1) design with G≤Aut D block primitive then G does not have a Suzuki group Sz(q) as the socle. 相似文献