共查询到20条相似文献,搜索用时 36 毫秒
1.
To every egglike inversive plane
there is associated a family
of involutions of the point set of
such that
circles of
are the fixed point sets of the involutions in
. Korchmaros and Olanda characterized a family
of involutions on a set of size n2 + 1to be
for
an egglike inversive plane of order n by four conditions. In this
paper, we give an alternative proof where the Galois space PG(3,n) in
which
is embedded is built up directly by using concepts and
results on finite linear spaces. 相似文献
2.
We study the existence of classical (non-collision) T-periodic
solutions of the Hamiltonian system
where
and
is a T-periodic function in t which has a
singularity at
like
Under suitable conditions on H, we prove that if
then (HS) possesses at least one
non-collision solution and if
then the generalized solution of (HS) obtained in [5] has at most
one time of collision in its period. 相似文献
3.
We study two questions posed by Johnson, Lindenstrauss, Preiss, and
Schechtman, concerning the structure of level sets of uniform and Lipschitz
quotient mappings from
. We show that if
, is a uniform quotient mapping then for every
has
a bounded number of components, each component of
separates
and the upper bound of the number of components depends
only on
and the moduli of co-uniform and uniform continuity of
.Next we prove that all level sets of any co-Lipschitz uniformly
continuous mapping from
to
are locally connected, and we show
that for every pair of a constant
and a function
with
, there exists a natural number
, so that
for every co-Lipschitz uniformly continuous map
with a
co-Lipschitz constant
and a modulus of uniform continuity
, there
exists a natural number
and a finite set
with
card
so that for all
has exactly
components,
has exactly
components and
each component of
is homeomorphic with the real line and
separates the plane into exactly 2 components. The number and form
of components of
for
are also described - they have a
finite tree structure. 相似文献
4.
Marilyn Breen 《Aequationes Mathematicae》2004,67(3):263-275
Summary.
We establish the following Helly-type result for infinite families
of starshaped sets in
Define the function f on
{1, 2} by
f(1) = 4,
f(2) = 3.
Let
be a fixed positive number, and let
be a uniformly bounded family of compact sets
in the plane. For k = 1, 2, if every
f(k)
(not necessarily distinct) members of
intersect in a starshaped set whose
kernel contains a k-dimensional
neighborhood of radius
, then
is a starshaped set whose kernel is at least
k-dimensional.
The number f(k) is best in each case.
In addition, we present a few results concerning the dimension of
the kernel in an intersection of starshaped sets in
Some of these involve finite families of sets, while others
involve infinite families and make use of the Hausdorff metric. 相似文献
5.
Consider the Dirichlet problem for the parabolic equation
in
, where
$\Omega$ is a bounded domain in
and f has superlinear subcritical growth in u.
If f is independent of t and satisfies some
additional conditions then using a dynamical method we find multiple (three, six or infinitely many) nontrivial
stationary solutions. If f has the form
where m is periodic, positive and m,g satisfy some technical
conditions then we prove the existence of a positive periodic solution and
we provide a locally uniform bound for all global solutions. 相似文献
6.
Let p be a prime,
a finite p-group,
any finite group with order divisible by p,
and
any action of
on
. We show that the cardinality of the set of all derivations
with respect to this action is a multiple of
p. This
generalises theorems of Frobenius and Hall.
Received: 16 June 2003 相似文献
7.
In this paper we shall consider the critical elliptic
equation
where
and a(x)
is a real continuous, non
negative function, not identically zero. By using a local Pohozaev
identity, we show that problem (0.1) does not admit a
family of solutions
which blows-up and concentrates as
at some zero point x0 of a(x)
if the order of flatness of the function a(x) at x0 is
相似文献
8.
Walter Benz 《Journal of Geometry》2004,79(1-2):19-26
Suppose that X is a real inner product
space of (finite or infinite) dimension at least 2. A distance preserving mapping
, where
is a (finite or infinite) subset of a
finite-dimensional subspace of X, can be extended
to an isometry
of X. This holds true for
euclidean as well as for hyperbolic geometry. To both geometries there exist examples
of non-extentable distance preserving
, where S
is not contained in a finite-dimensional subspace of
X. 相似文献
9.
A class of bounded operators on Sobolev spaces 总被引:2,自引:0,他引:2
We describe a class of nonlinear operators which are bounded on the
Sobolev spaces
, for
and 1 < p <
. As a corollary, we prove that the Hardy-Littlewood maximal operator is bounded on
, for
and 1 < p <
; this extends the result of J. Kinnunen [7], valid for s = 1.
Received: 5 December 2000 相似文献
10.
Mark Pankov 《Journal of Geometry》2004,79(1-2):169-176
Let
be a finite-dimensional projective space
and
be the Grassmannian consisting of
all k-dimensional subspaces of
. In the paper we show that
transformations of
sending base subsets
to base subsets are induced by collineations of
to itself or to the dual projective space
.
This statement generalizes the main result of the authors paper [19]. 相似文献
11.
It is well known that (i) for every irrational number the Kronecker
sequence m (m = 1,...,M) is equidistributed modulo one in the
limit
, and (ii) closed horocycles of length
become equidistributed
in the unit tangent bundle
of a hyperbolic surface
of finite area, as
. In the present paper both equidistribution
problems are studied simultaneously: we prove that for any constant
the Kronecker sequence embedded in
along a long closed
horocycle becomes equidistributed in
for almost all , provided
that
. This equidistribution result holds in fact under
explicit diophantine conditions on (e.g. for = 2) provided that
,
with additional assumptions on the Fourier coefficients
of certain automorphic forms. Finally, we show that for
, our
equidistribution theorem implies a recent result of Rudnick and Sarnak
on the uniformity of the pair correlation density of the sequence
n2 modulo one. 相似文献
12.
Let X be a Banach space and let
A be a closed linear operator on
X. It is shown that the abstract Cauchy problem
enjoys maximal regularity in weighted
L
p
-spaces with weights
, where
,
if and only if it has the property of maximal
L
p
-regularity.
Moreover, it is also shown that the derivation operator
admits an
-calculus in weighted
L
p
-spaces.
Received: 26 February 2003 相似文献
14.
15.
Under the assumption of the Riemann hypothesis the
asymptotic value y/log x is known to hold for the number of
primes in the short interval [x - y, x] for
for
every fixed
.
We show under the assumption
of the existence of exceptional Dirichlet characters the same
asymptotic formula holds in the shorter intervals, for some
\, in wide ranges of x depending on the
characters. 相似文献
16.
Let
be the Hecke algebra of the symmetric group
over a field K of characteristic
and
a primitive
-th root of one in K. We show that an
-module is projective if and only if its restrictions to any
-parabolic subalgebra of
is projective.
Moreover, we give a new construction of blocks of
-parabolic subalgebras, in terms of skew group algebras over local commutative
algebras.
Received: 30 June 2003 相似文献
17.
Consider the Schrödinger operator
with a complex-valued
potential v of period
Let
and
be the eigenvalues of L that are close to
respectively, with periodic (for n even),
antiperiodic (for n odd), and Dirichelet
boundary conditions on [0,1], and let
be the diameter of the spectral
triangle with vertices
We prove the following statement: If
then v(x) is a Gevrey function, and moreover
相似文献
18.
Let C be a set of objects in a triangulated compactly generated category
We denote by
the smallest suspended subcategory closed under coproducts which contains C (the smallest cosuspended subcategory closed under products which contains
C). We prove that if C is a set of compacts objects then
is a t-structure in
where TC
I is the dual of C with respect to an injective cogenerator
I in the category Mod
C. Moreover, we show that:
C is a tilting set if and only if
And, this is equivalent to TCI is a cotilting object in
Received: 28 March 2003 相似文献
19.
Let
be the L
2-critical nonlinear Schr?dinger equation, in a domain
with initial data in
(Dirichlet boundary condition) and
. We prove existence and stability of finite time blow-up dynamics with the log-log blow-up speed
Moreover, for a suitable class of finite time blow-up solutions, we derive global rigidity properties which turn out to be
modeled after the
ones.
Submitted: October 14, 2005. Revised: October 26, 2006. Accepted: February 2, 2007. 相似文献
20.
In this paper we construct certain moduli spaces, which we call
moduli spaces of (principal) F-bundles,
and study their basic properties. These spaces are
associated to triples consisting of a smooth projective geometrically
connected curve over a finite field, a split
reductive group G, and an irreducible
algebraic representation
.of
of
Our spaces generalize moduli
spaces of F-sheaves, studied
by Drinfeld and Lafforgue, which correspond to the case G
= GLr
and
is the tensor product of the standard
representation and its dual. The importance of the moduli spaces
of F-bundles is due to the
belief that Langlands correspondence is realized in their cohomology. 相似文献