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1.
Estimates of Marcinkiewicz Integrals with Bounded Homogeneous Kernels of Degree Zero 总被引:2,自引:0,他引:2
Under the cancellation property and a certain Dini-type condition
on kernels, we prove that Marcinkiewicz integrals with kernels which are homogeneous
functions of degree zero, are bounded from
to
,
from
to
, and from
to
for
. 相似文献
2.
The solutions of the equation
in
, where
are investigated,
Bessel potentials of higher order are defined, and recurrence relations
between these solutions and these Bessel potentials are obtained. It is
also proved that these solutions and the solutions of
, under certain conditions, are identical.
Received: 6 November 2002 相似文献
3.
Marilyn Breen 《Archiv der Mathematik》2005,84(3):282-288
Let k and d be fixed integers, 0kd, and let
be a collection of sets in
If every countable subfamily of
has a starshaped intersection, then
is (nonempty and) starshaped as well. Moreover, if every countable subfamily of
has as its intersection a starshaped set whose kernel is at least k-dimensional, then the kernel of
is at least k-dimensional, too. Finally, dual statements hold for unions of sets.Received: 3 April 2004 相似文献
4.
We prove a product formula which involves the unitary group generated by a semibounded self-adjoint operator and an orthogonal projection P on a separable Hilbert space
with the convergence in
It gives a partial answer to the question about existence of the limit which describes quantum Zeno dynamics in the subspace Ran P. The convergence in
is demonstrated in the case of a finite-dimensional P. The main result is illustrated in the example where the projection corresponds to a domain in
and the unitary group is the free Schrödinger evolution.submitted 21/06/04, accepted 12/10/04 相似文献
5.
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
6.
A finite group whose irreducible complex characters are rational is called a
-group. In this paper we will find the structure of Frobenius
-groups.Received: 14 April 2003 相似文献
7.
Let S be a real interval with
, and
be a function satisfying
We show that if h is Lebesgue or Baire measurable, then there
exists
such that
That result is motivated by a question of E. Manstaviius.
Received: 11 February 2003 相似文献
8.
We study the application,
, where
is the
supremum of positive s such that the problem
admits a solution. Where B 1 is the unit ball in
We show that
is a decreasing function, with
where
is the unique solution of the
problem
.
We also give the explicit solutions of the problem
, when
and show that
. We show that the problem
doesnt admit a solution.
In the end, we give a numerical approximation of
, when
. 相似文献
9.
In this note we prove the uniqueness of U in a group G with
a spherical split-BN-pair of rank
,i.e., if G has such a BN-pair with
a nilpotent normal subgroup of B,
and
, then
and
is a normal subgroup of G. Here
is the corresponding group of Lie-type and
the subgroup of
generated by all root-subgroups corresponding to positive roots.
Received: 19 May 2003 相似文献
10.
Summary.
Let
We say that
preserves the distance d 0 if
for each
implies
Let A
n
denote the set of all positive numbers
d such that any map
that preserves unit distance preserves also distance
d.
Let D
n
denote the set of all positive numbers
d with the property: if
and
then there exists a finite set
S
xy
with
such that any map
that preserves unit distance preserves also the distance between
x and y.
Obviously,
We prove:
(1)
(2)
for n 2
D
n
is a
dense subset of
(2) implies that each mapping
f
from
to
(n 2)
preserving unit distance preserves all distances,
if f is continuous with respect to the product topologies
on
and
相似文献
11.
Hans-Peter Schröcker 《Journal of Geometry》2005,82(1-2):172-187
We study the projective space
of univariate rational parameterized equations of degree d or less in real projective space
The parameterized equations of degree less than d form a special algebraic variety
We investigate the subspaces on
and their relation to rational curves in
give a geometric characterization of the automorphism group of
and outline applications of the theory to projective kinematics. 相似文献
12.
B. Scarpellini 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,56(3):412-438
In this paper we consider the magnetic Couette-Taylor problem, that is, a conducting fluid between two infinite rotating cylinders, subject to a magnetic field parallel to the rotation axis. This configuration admits an equilibrium solution of the form
It is shown that this equilibrium is Ljapounov stable under small perturbations in
where
provided that the parameters a, b, , are small. The methods of proof are a combination of an energy method, based on Bloch space analysis and small data techniques.Received: February 5, 2003; revised: September 29, 2003Dedicated to Prof. H. Amann on the occasion of his 65. birthday 相似文献
13.
R. B. Kusner [R. Guy, Amer. Math. Monthly 90, 196-199 (1983)]
asked whether a set of vectors in
such that the
distance between any pair is 1, has cardinality at most
d + 1.
We show that this is true for p = 4
and any
, and false for all 1<p<2 with d sufficiently large, depending on p. More
generally we show that the maximum cardinality is at most
if p is an even integer, and at least
if 1<p<2, where
depends on p.
Received: 5 May 2003 相似文献
14.
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
15.
In this paper, using the generalized Wronskian, we obtain a new sharp
bound for the generalized Masons theorem [1] for functions of several variables.
We also show that the Diophantine equation (The generalized Fermat-Catalan equation)
where
, such that k out of the
n-polynomials
are constant, and
under certain conditions for
has no non-constant solution.
Received: 20 March 2003 相似文献
16.
Let G be a finite group,
a normal subgroup, p a prime,
a finite splitting field of characteristic p for
G and
We prove that
is a splitting field for N, using the action
of the Galois group of the field extension
on the irreducible representations of N.
As
is a splitting field for the symmetric group
Sn
we get as a corollary that
is a splitting field for the alternating group
An.
Received: 31 July 2003 相似文献
17.
Let
denote a Feller semigroup on
, and
itsextension to the bounded measurable functions. We show that
. If the generator of the semigroup is a pseudo-differential operator we can restate this condition in terms of the symbol. As a by-product, we obtain necessary and sufficient conditions for the conservativeness of the semigroup which are again expressed through the symbol. 相似文献
18.
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
19.
Emil Saucan 《Mediterranean Journal of Mathematics》2005,2(2):215-229
We prove that given a
Riemannian manifold with boundary, having a finite number of compact boundary components, any fat triangulation of the boundary can be extended to the whole manifold. We also show that this result extends to
manifolds and to embedded PL manifolds of dimensions 2, 3 and 4. We employ these results to prove that manifolds of the types above admit quasimeromorphic mappings onto
As an application we prove the existence of G-automorphic quasimeromorphic mappings, where G is a Kleinian group acting on
Dedicated to the memory of Robert BrooksThis paper represents part of the authors Ph.D. thesis written under the supervision of Prof. Uri Srebro. 相似文献
20.
ALAIN HÉNAUT 《Geometriae Dedicata》1997,65(1):89-101
A d-web in (
,0) is given by d complex analytic foliations of codimension one in (
,0) which are in general position. A d-web
in (
,0) is linear if all the leaves are (pieces of) hyperplanes in
and
is algebraic if it is associated, by duality, to a nondegenerate algebraic curve in
of degree d. We characterize linear webs in (
,0). We give explicit conditions under which a linear d-web in (
,0) is algebraic and we obtain equations for
in this case. Some related problems are discussed and some questions are posed. 相似文献