The Berezin and Garding Inequalities

Let ? be a convex function on ?, let ?(σ) be a pseudodifferential operator with symbol σ, let Λ_σ be the set of its eigenvalues, and let m(λ) be the multiplicity of an eigenvalue λ ∈ Λ_σ. Under certain natural assumptions about properties of pseudodifferential operators, we prove that \(\sum {_{\lambda \in \Lambda _\sigma } m(\lambda )} \varphi (\lambda ) \leqslant \operatorname{Tr} L(\varphi (\sigma )) + R\), where R is an error term of the same order as the remainder term in the Garding inequality.     

Some necessary and sufficient conditions for Hypercyclicity Criterion

We give necessary and sufficient conditions for an operator on a separable Hilbert space to satisfy the hypercyclicity criterion. This paper is a part of the second author’s Doctoral thesis, written at Shiraz University under the direction of the first author.     

C~n中Dirichlet型空间和Bloch型空间上的加权Cesàro算子

本文在Cn中单位球上讨论了Dirichlet型空间Dp,Bloch型空间βp以及Lipschitz空间Ap上加权Cesaro算子Tg的有界性和紧性.得到当P<0,q≤P 2或P>n,q≤P 2时,Tg是Dp到Dq的有界算子或紧算子的充要条件;对所有的P,q,获得了Tg是βp到βq之有界算子和紧算子的充要条件及Tg是β0p到β0q之有界算子的充要条件等.     

Dirichlet空间上的超循环复合算子

设Bn是复平面C中的单位圆盘(n=1)或复空间Cn中的单位球.众所周知,在Hardy空间上存在丰富的符号在Aut(Bn)中的超循环复合算子.然而,在复平面中单位圆盘上的Dirichlet空间中, 任何复合算子都不能是超循环的.本文则证明,当n>1时,Bn上的Dirichlet空间中确有超循环复合算子.     

含H-单调映象的完全广义非线性变分包含

引入和研究了一类新的完全广义非线性变分包含.在Hilbert空间中利用与H-单调映象相联系的预解算子的性质,对完全广义非线性变分包含建立了解的存在性定理和构造了一种新的迭代算法,证明了由此算法生成的迭代序列强收敛于精确解.其算法和结果是最近文献中相应算法和结果的改进和推广.     

算子权移位的换位代数的交换性

令T是以{Wk}∞k=1B(Cn)为权序列的内射算子权移位.设T是强不可约的,而且sup1k<∞‖W-1k‖< ∞.用A′(T)表示T的换位代数,radA′(T)表示A′(T)的Jacobson根.本文刻划了radA′(T)并且证明了商代数A′(T)/radA′(T)是交换的.     

一个增算子不动点定理及其在Banach 空间非线性方程的应用

给出了Banach空间的一个增算子不动点定理,将这一定理应用到Banach空间的积分-微分方程,给出了一类积分-微分方程的连续可微最大解和连续可微最小解的存在性定理.     

Boundedness of Multilinear Operators on Herz Type Spaces： Extreme Cases

In this paper, two classes of closely related multilinear singular and fractional integrals,which include the commutators as special cases, are studied and their boundedness on Herz type spaces is discussed. In fact, it is proved that these operators are actually not bounded in certain extreme cases.     

Second Order Nonlinear Evolution Inclusions Ⅰ： Existence and Relaxation Results

This is the first part of a work on second order nonlinear, nonmonotone evolution inclusions defined in the framework of an evolution triple of spaces and with a multivalued nonlinearity depending on both x（t） and x（t）. In this first part we prove existence and relaxation theorems. We consider the case of an usc, convex valued nonlinearity and we show that for this problem the solution set is nonempty and compact in C^1 （T, H）. Also we examine the Isc, nonconvex case and again we prove the existence of solutions. In addition we establish the existence of extremal solutions and by strengthening our hypotheses, we show that the extremal solutions are dense in C^1 （T, H） to the solutions of the original convex problem （strong relaxation）. An example of a nonlinear hyperbolic optimal control problem is also discussed.     

A partial differential equation connected to option pricing with stochastic volatility: Regularity results and discretization

This paper completes a previous work on a Black and Scholes equation with stochastic volatility. This is a degenerate parabolic equation, which gives the price of a European option as a function of the time, of the price of the underlying asset, and of the volatility, when the volatility is a function of a mean reverting Orstein-Uhlenbeck process, possibly correlated with the underlying asset. The analysis involves weighted Sobolev spaces. We give a characterization of the domain of the operator, which permits us to use results from the theory of semigroups. We then study a related model elliptic problem and propose a finite element method with a regular mesh with respect to the intrinsic metric associated with the degenerate operator. For the error estimate, we need to prove an approximation result.