Limits of discrete series with infinitesimal character zero

For a connected linear semisimple Lie group , this paper considers those nonzero limits of discrete series representations having infinitesimal character 0, calling them totally degenerate. Such representations exist if and only if has a compact Cartan subgroup, is quasisplit, and is acceptable in the sense of Harish-Chandra.

Totally degenerate limits of discrete series are natural objects of study in the theory of automorphic forms: in fact, those automorphic representations of adelic groups that have totally degenerate limits of discrete series as archimedean components correspond conjecturally to complex continuous representations of Galois groups of number fields. The automorphic representations in question have important arithmetic significance, but very little has been proved up to now toward establishing this part of the Langlands conjectures.

There is some hope of making progress in this area, and for that one needs to know in detail the representations of under consideration. The aim of this paper is to determine the classification parameters of all totally degenerate limits of discrete series in the Knapp-Zuckerman classification of irreducible tempered representations, i.e., to express these representations as induced representations with nondegenerate data.

The paper uses a general argument, based on the finite abelian reducibility group attached to a specific unitary principal series representation of . First an easy result gives the aggregate of the classification parameters. Then a harder result uses the easy result to match the classification parameters with the representations of under consideration in representation-by-representation fashion. The paper includes tables of the classification parameters for all such groups .

     

Singular Integrals and Potential Theory

In this paper I consider a class of non-standard singular integrals motivated by potential theoretic and probabilistic considerations. The probabilistic applications, which are by far the most interesting part of this circle of ideas, are only outlined in Section 1.5: They give the best approximation of the solution of the classical Dirichlet problem in a Lipschitz domain by the corresponding solution by finite differences. The potential theoretic estimate needed for this gives rise to a natural duality between the L _p functions on the boundary ∂Ω and a class of functions A on Ω that was first considered by Dahlberg. The actual duality is given by ∫_Ω S f(x)A(x)dx = (f, A) where S f(x) = ∫_∂Ω |x − y|¹⁻ⁿ f(y)dy is the Newtonian potential. We can identify the upper half Lipschitz space with in the obvious way and express for an appropriate kernel K. It is the boundedness properties of the above (for , ) that is the essential part of this work. This relates with more classical (but still “rough”) singular integrals that have been considered by Christ and Journé. Lecture held in the Seminario Matematico e Fisico on March 14, 2005 Received: April 2007     

计算应力强度因子的离散分离变量法

提出一种用于数值求解带有一条边界裂纹的多角形区域上的Navier's方程组边值问题的半离散方法。做一个适当的坐标变换后,将原边值问题化为半无限长条上的不连续系数问题。将其半离散化以后,等价于一个常系数常微分方程组的边值问题。进一步,用直接法来求解这个边值问题,便得到原问题的半离散近似解。值得指出的是,这个用分离变量形式给出的半离散近似解自然地具有原问题的奇性。数值例子显示,用该方法可以很方便地计算出在裂纹顶端的应力强度因子的近似值。     

三维位势问题边界元法中几乎奇异积分的正则化

采用一种半解析正则化算法,计算了三维位势问题边界元法中近边界点的几乎强奇异和几乎超奇异面积分.该算法适用于三角形线性等参元.对高次单元将其细分为几个三节点三角形单元即可应用该算法.由于几乎奇异性,与内点邻近的单元上的积分,采用半解析正则化积分算法计算;而远处单元的积分仍保持常规高斯积分.对三维热传导算例,计算了近边界点的温度和热流.数值结果证明了该算法的有效性和精确性.     

The solution of integral equations with strongly singular kernels applied to the torsion of cracked circular cylinder

In this paper,the functions of warping displacement interruption defined on the crack lines are taken for the fundamental unknown functions.The torsion problem of cracked circular cylinder is reduced to solving a system of integral equations with strongly singular kernels.Using the numerical method of these equations,the torsional rigidities and the stress intensity factors are calculated to solve the torsion problem of circular cylinder with star-type and other different types of cracks.The numerical results are satisfactory.     

Singular perturbation solutions of the nonlinear stability of a truncated shallow shperical shell under linear distributed loads along the interior edge

Using a singular perturbation method,the nonlinear stability of a truncated shallow,spherical shell without a nondeformable rigid body at the center under linear distributed loads along the interior edge is investigated in this paper.When the geometrical parameter k is large,the uniformly valid asymptotic solutions are obtained.     

正交异性半无限固支板条的弹性解

正交异性半无限固支板条在表面为应力自由和在无穷远处受载时的弹性解的控制微分方程为φ,yyyy+(2+δ₀)φ,yyzz+φ,zzzz=0(δ₀>-4).基于文献[10]对δ₀>0情形的工作,本文完成对各向同性材料δ₀=0和正交异性材料0>δ₀>-4情形的讨论.上述问题的解在边界位移数据给定情形的板理论的边界条件的合理提法方面有重要应用.     

TOPOLOGICAL STRUCTURE OF THE SINGULAR POINTS OF THE THIRD ORDER PHASE LOCKED LOOP EQUATIONS WITH THE CHARACTER OF DETECTED PHASE BEING g(φ)=(1+k)sinφ/(1+kcosφ)

In this paper, we study the topological structure of the singular points of the third order phase locked loop equations with the character of detected phase being g(φ)=(1+k)sinφ/1+kcosφ.     

关于齐次群上的奇异积分

本文对文[3]中引进的齐次群N(Q)=(R~n×C~m,O)上的奇异积分作了一些讨论.设L(Z)是C~m上的-2m次齐次广义函数,且L(z)∈C~∞(C~m/({0}).令K(t,z)=L(z)6(t),K_s(t,z)=K(t,z)·x(|(t,z)|>e).本文证明了算子Af=f*K及A_,f=f*K_e均可延拓为L~p(N(噩))上的有界算子,1相似文献   

Boundary and interior layer behavior for singularly perturbed vector problem

In this paper,we consider the vector nonlinear boundary value problem:εy~v=f(x,y,z,y′,ε),y(0)=A_1,y(1)=B_1εz~v=g(x,y,z,z′,ε),z(0)=A_2,z(1)=B_2whereε>0 is a small parameter,0≤x≤1 ,f and g are continuous functions in R~4,Under appropriate assumptions,by means of the differential inequalities,we demonstratethe existence and estimation,involving boundary and interior layers,of the solutions to theabove problem.