共查询到20条相似文献,搜索用时 31 毫秒
1.
Antonio Azzollini Vieri Benci Teresa D’Aprile Donato Fortunato 《Ricerche di matematica》2006,55(2):123-137
Abstract In this paper we study a model which describes the relation of the matter and the electromagnetic field from a unitarian standpoint in the spirit of the ideas of Born and Infeld. This model, introduced in [1], is based on a semilinear perturbation of the
Maxwell equation (SME). The particles are described by the finite energy solitary waves of SME whose existence is due to the
presence of the nonlinearity. In the magnetostatic case (i.e. when the electric field
and the magnetic field
does not depend on time) the semilinear Maxwell equations reduce to semilinear equation
where “
” is the curl operator, f′ is the gradient of a smooth function
and
is the gauge potential related to the magnetic field
(
). The presence of the curl operator causes (1) to be a strongly degenerate elliptic equation. The existence of a nontrivial
finite energy solution of (1) having a kind of cylindrical symmetry is proved. The proof is carried out by using a variational
approach based on two main ingredients: the Principle of symmetric criticality of Palais, which allows to avoid the difficulties due to the curl operator, and the concentration-compactness argument combined
with a suitable minimization argument.
Keywords: Maxwell equations, Natural constraint, Minimizing sequence
Mathematics Subject Classification (2000): 35B40, 35B45, 92C15 相似文献
2.
We introduce the set of bicomplex numbers
which is a commutative ring with zero divisors defined by
where
We present the conjugates and the moduli associated with the bicomplex numbers. Then we study the bicomplex Schr?dinger equation
and found the continuity equations. The discrete symmetries of the system of equations describing the bicomplex Schr?dinger
equation are obtained. Finally, we study the bicomplex Born formulas under the discrete symmetries. We obtain the standard
Born’s formula for the class of bicomplex wave functions having a null hyperbolic angle. 相似文献
3.
Abstract Consider an interstellar cloud that occupies the region
, bounded by the known surface
, and assume that the scattering cross section σs and the total cross section σ are also known. Then, we prove that it is possible to identify the source q=q(x,t) that produces UV-photons inside the cloud, provided that the UV-photon distribution function arriving at a location
, far from the cloud, is measured at times
,
, ...,
.
Keywords: Photon transport, Semigroups and linear evolution equations, Inverse problems
Mathematics Subject Classification (2000): 82A25, 82C70, 34K29, 65M32 相似文献
4.
Abstract We give complete algebraic characterizations of the Lp-dissipativity of the Dirichlet problem for some systems of partial differential operators of the form
, where
are m× m matrices. First, we determine the sharp angle of dissipativity for a general scalar operator with complex coefficients. Next
we prove that the two-dimensional elasticity operator is Lp-dissipative if and only if
ν being the Poisson ratio. Finally we find a necessary and sufficient algebraic condition for the Lp-dissipativity of the operator
, where
are m× m matrices with complex L1loc entries, and we describe the maximum angle of Lp-dissipativity for this operator.
Keywords: Lp-dissipativity, Algebraic conditions, Elasticity system
Mathematics Subject Classification (2000): 47D03, 47D06, 47B44, 74B05 相似文献
5.
We consider the perturbed harmonic oscillator
in
, where
is a real-valued potential. We prove that the mapping
spectral data = {eigenvalues of T
D
}
{norming constants} is one-to-one and onto. The complete characterization of the set of spectral data which corresponds to
is given.
Dedicated to Vladimir Buslaev on the occasion of his 70th birthday
Submitted: September 27, 2006. Accepted: January 9, 2007. 相似文献
6.
Humio Ichimura 《Archiv der Mathematik》2006,87(6):539-545
Let p be an odd prime number and
. Let
be the classical Stickelberger ideal of the group ring
. Iwasawa [6] proved that the index
equals the relative class number
of
. In [2], [4] we defined for each subgroup H of G a Stickelberger ideal
of
, and studied some of its properties. In this note, we prove that when
mod 4 and [G : H] = 2, the index
equals the quotient
.
Received: 13 January 2006 相似文献
7.
Alina Iacob 《Archiv der Mathematik》2005,85(4):335-344
We consider two pairs of complete hereditary cotorsion theories
on the category of left R-modules, such that
We prove that for any left R-modules M, N and for any n ≧ 1, the generalized Tate cohomology modules
can be computed either using a left
of M and a left
of M or using a right
a right
of N.
Received: 17 December 2004 相似文献
8.
Let G be a connected simply connected almost
-simple algebraic group with
non-compact and
a cocompact congruence subgroup. For any homogeneous manifold
of finite volume, and a
, we show that the Hecke orbit T
a
(x
0
H) is equidistributed on
as
, provided H is a non-compact commutative reductive subgroup of G. As a corollary, we generalize the equidistribution result of Hecke points ([COU], [EO1]) to homogeneous spaces G/H. As a concrete application, we describe the equidistribution result in the rational matrices with a given characteristic
polynomial.
The second author partially supported by DMS 0333397.
Received: May 2005 Revision: March 2006 Accepted: June 2006 相似文献
9.
Let m ≥ 1 be an integer and N > 2m. Let μ be a positive Radon measure on . We study necessary and sufficient conditions on possible distributional solutions of , that guarantee the validity of the representation formula a.e. on , where and c(2m) is a positive constant depending on m and N. Several consequences are derived. In particular we prove Liouville theorems for systems of higher order elliptic inequalities
and weighted form of Hardy-Littlewood-Sobolev systems of integral equations.
Received: March 2008 相似文献
10.
Let G be a split adjoint semisimple group over
and
a maximal compact subgroup. We shall give a uniform, short and essentially elementary proof of the Weyl law for cusp forms
on congruence quotients of
. This proves a conjecture of Sarnak for
-split groups, previously known only for the case G = PGL(n). The key idea amounts to a new type of simple trace formula.
Received: April 2005 Revision: June 2006 Accepted: October 2006 相似文献
11.
Abstract Let p be a prime integer and M a Krull monoid with divisor class group
. We represent by S the set of nontrivial divisor classes of
which contain prime divisors. We present a new inequality for the elasticity of M (denoted ρ (M)) which is dependent on the cardinality of S and argue that this inequality is the best possible. If M as above has | S| = 3, then it is known that
, but for large p, not all the values in this containment set can be realized. For each | S| = 3, we produce a submonoid
of
such that
Keywords: Krull monoid, Block monoid, Elasticity of factorization
Mathematics Subject Classification (2000): 20M14, 20D60, 13F05 相似文献
12.
Precise Asymptotics in the Law of the Iterated Logarithm of Moving-Average Processes 总被引:1,自引:0,他引:1
Yun Xia LI Li Xin ZHANG 《数学学报(英文版)》2006,22(1):143-156
In this paper, we discuss the moving-average process Xk = ∑i=-∞ ^∞ ai+kεi, where {εi;-∞ 〈 i 〈 ∞} is a doubly infinite sequence of identically distributed ψ-mixing or negatively associated random variables with mean zeros and finite variances, {ai;-∞ 〈 i 〈 -∞) is an absolutely solutely summable sequence of real numbers. 相似文献
13.
Analysis of an Age Structured SEIRS
Epidemic Model with Varying Total Population Size and Vaccination 总被引:3,自引:0,他引:3
Xue-Zhi Li~ Geni Gupur~ Guang-Tian Zhu~ Department of Mathematics Xinyang Teachers College Henan China 《应用数学学报(英文版)》2004,20(1):25-36
This article focuses on the study of an age structured SEIRS epidemic model with a vaccinationprogram when the total population size is not kept at constant.We first give the explicit expression of thereproduction number R(ψ,(?)) in the presence of vaccine ((?) is the exponent of growth of total population),andshow that the infection-free steady state is linearly stable if R(ψ,(?))<1 and unstable if R(ψ,(?))>1,then weapply the theoretical results to vaccination policies to determine the optimal age or ages at which an individualshould be vaccinated.It is shown that the optimal strategy can be either one- or two-age strategies. 相似文献
14.
Karl-Theodor Sturm 《Acta Mathematica》2006,196(1):65-131
We introduce and analyze lower (Ricci) curvature bounds
⩾ K for metric measure spaces
. Our definition is based on convexity properties of the relative entropy
regarded as a function on the L
2-Wasserstein space of probability measures on the metric space
. Among others, we show that
⩾ K implies estimates for the volume growth of concentric balls. For Riemannian manifolds,
⩾ K if and only if
⩾ K
for all
.
The crucial point is that our lower curvature bounds are stable under an appropriate notion of D-convergence of metric measure spaces. We define a complete and separable length metric D on the family of all isomorphism classes of normalized metric measure spaces. The metric D has a natural interpretation, based on the concept of optimal mass transportation.
We also prove that the family of normalized metric measure spaces with doubling constant ⩽ C is closed under D-convergence. Moreover, the family of normalized metric measure spaces with doubling constant ⩽ C and diameter ⩽ L is compact under D-convergence. 相似文献
15.
E. M. E. Zayed 《数学学报(英文版)》2000,16(4):627-636
Abstract
Small-time asymptotics of the trace of the heat semigroup
where {μ
ν
} are the eigenvalues of the negative Laplacian
in the (x
1, x
2)-plane, is studied for a general bunded domain Ω with a smooth boundary ∂Ω, where a finite number of Dirichlet, Neumann and
Robin boundary conditions, on the piecewise smooth parts Γ
i
(i = 1, ..., n) of ∂Ω such that
, are considered. Some geometrical properties associated with Ω are determined. 相似文献
16.
Adimurthi K. Sandeep 《NoDEA : Nonlinear Differential Equations and Applications》2007,13(5-6):585-603
Let Ω be a bounded domain in
, we prove the singular Moser-Trudinger embedding:
if and only if
where
and
. We will also study the corresponding critical exponent problem. 相似文献
17.
This work is a complement to the authors earlier papers, where it is shown that a functor category
inherits from
such properties as amalgamation, transferability and congruence extension if
has either products or certain pushouts. A general scheme is given for constructing counter-examples which show that the latter condition on
is essential. In particular, it is shown that the functor categories
,
,
(
resp.) do not satisfy the amalgamation (congruence extension resp.) property in general. Moreover, one class of categories is described, where the condition of the existence of certain pushouts is not only sufficient, but also necessary for
to preserve the considered properties of
.Mathematics Subject Classifications (2000) 18A25, 18A32, 18B99, 08B26.Dali Zangurashvili: The support rendered by INTAS Grant 97 31961 is gratefully acknowledged. 相似文献
18.
Lutz Strüngmann 《Archiv der Mathematik》2006,86(3):193-204
Let R be a unital associative ring and
two classes of left R-modules. In this paper we introduce the notion of a
In analogy to classical cotorsion pairs as defined by Salce [10], a pair
of subclasses
and
is called a
if it is maximal with respect to the classes
and the condition
for all
and
Basic properties of
are stated and several examples in the category of abelian groups are studied.
Received: 17 March 2005 相似文献
19.
Precise asymptotics in the Baum-Katz and davis law of large numbers for positively associated sequences 总被引:6,自引:1,他引:5
§ 1 Introduction and resultsL et { X,Xi;i≥ 1} be a sequence of i.i.d.random variables,and set Sn= ni=1 Xi,n≥1.Hsu and Robbins[1 ] introduced the conceptof complete convergence.They together withErdos[2 ] proved n≥ 1 P(|Sn|≥εn) <∞ ,ε>0 (1)if and only if EX=0 and EX2 <∞ .L ater,Spitzer[3] proved n≥ 11n P(|Sn|≥εn) <∞ ,ε>0if and only if EX =0 and E|X|<∞ .More generally,it was shown by Baum and Katz[4 ]that,for 0
0 (… 相似文献
20.
We define the reduced minimum modulus
of a nonzero element a in a unital C
*-algebra
by
. We prove that
. Applying this result to
and its closed two side ideal
, we get that dist
,
and
for any
if RR
= 0, where
and
is the quotient homomorphism and
. These results generalize corresponding results in Hilbert spaces. 相似文献