逐次有理L_2逼近

逐次有理Ｌ_２逼近潘杰（合肥工业大学）ＳＵＣＣＥＳＳＩＶＥＲＡＴＩＯＮＡＬＬ＿２－ＡＰＰＲＯＸＩＭＡＴＩＯＮ￥ＰａｎＪｉｅ（ＨｅｆｅｉＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ）Ａｂｓｔｒａｃｔ：Ｌｅｔｆｕｎｃｔｉｏｎｆ∈Ｌ２［ａ，ｂ］，ｒａｔｉｏ?..     

On the Structure of the B—cocleft Module Coalgebra

§１．　ＴｈｅＥｑｕｉｖａｌｅｎｔＴｈｅｏｒｅｍｏｆｔｈｅＣｒｏｓｓｅｄＣｏｐｒｏｄｕｃｔＬｅｔＣｂｅａｌｅｆｔＨ－ｗｅａｋｌｙｃｏｍｏｄｕｌｅｃｏａｌｇｅｂｒａ［４］ｗｉｔｈｔｈｅｓｔｒｕｃｔｕｒｅρ－Ｃ（ｃ）＝∑ｃ（１）ｃ（２）．ＤｂｅｌｅｆｔＨ－ｍｏｄｕｌｅｃｏａｌｇｅｂｒａ［２］ｗｉｔｈｔｈｅｓｔｒｕｃｔｕｒｅ“”．Ｆｏｒα∈Ｈｏｍκ（Ｃ，ＨＨ）ｄｅｎｏｔｅα（ｃ）＝∑α１（ｃ）α２（ｃ）．Ｄｅｆｉｎｅ△－：ＣＤ→（ＣＤ）（ＣＤ）ａｎｄε－：ＣＤ→κａｓｆｏｌｌｏｗ－ｉ…     

QUASI－CONVEX MULTIOBJECTIVE GAME－SOLUTION CONCEPTS，EXISTENCE AND SCALARIZATION

ＱＵＡＳＩ－ＣＯＮＶＥＸＭＵＬＴＩＯＢＪＥＣＴＩＶＥＧＡＭＥ－ＳＯＬＵＴＩＯＮＣＯＮＣＥＰＴＳ，ＥＸＩＳＴＥＮＣＥＡＮＤＳＣＡＬＡＲＩＺＡＴＩＯＮ￥ＬＩＹＵＡＮＸＩＡｂｓｔｒａｃｔ：Ｔｈｉｓｐａｐｅｒｄｅａｌｓｗｉｔｈｔｈｅｓｏｌｕｔｉｏｎｃｏｎｃｅ...     

LIMIT SETS OF A CLASS OF FOUR-DIMENSIONAL COMPETITIVE SYSTEMS

ＬＩＭＩＴＳＥＴＳＯＦＡＣＬＡＳＳＯＦＦＯＵＲ－ＤＩＭＥＮＳＩＯＮＡＬＣＯＭＰＥＴＩＴＩＶＥＳＹＳＴＥＭＳＲｕａｎＪｉａｎｃｈｅｎｇ（阮建成）（ＪｉｎａｎＵｎｉｖｅｒｓｉｔｙ）Ａｂｓｔｒａｃｔ：Ａ．Ｊ．Ｓｃｈｗａｒｔｚ［９］ｓｔｕｄｉｅｄＣ２ｄｙｎａ...     

An Interpretation of the Poincare Morphism for Compact Toric Varieties

ＡｎＩｎｔｅｒｐｒｅｔａｔｉｏｎｏｆｔｈｅＰｏｉｎｃａｒéＭｏｒｐｈｉｓｍｆｏｒＣｏｍｐａｃｔＴｏｒｉｃＶａｒｉｅｔｉｅｓ￥Ｊｅａｎ－ＰａｕｌＢＲＡＳＳＥＬＥＴ（ＣＩＲＭ－Ｍａｒｓｅｉｌｌｅ－ＦｒａｎｃｅＳｉＧｍＡＣＮＲＳ，ＣＩＲＭＬｕｍｉｎｙＣａｓ...     

系数在基本Harish—Chandra模中的Virasoro代数的上同调群

设ｇ为特征为０的二次闭域上的Ｖｉｒａｓｏｒｏ代数。本文决定了Ｈ＾１（ｇ，Ｍ（４，１）），Ｈ＾２（ｇ，Ｍ（４，２））及Ｈ＾２（ｇ，ＭＬ）的结构，其中Ｍ（４，１），Ｍ（４，２）为两类基本Ｈａｒｉｓｈ－Ｃｈａｎｄｒａ模，ＭＬ为无常数项单变量Ｌａｕｒｅｎｔ多项式。     

sl_2(R)上Harish-Chandra模及其应用

将ｓｌ２（Ｒ）上不可约Ｈａｒｉｓｈ－Ｃｈａｎｄｒａ模及ｓｌ２（Ｒ）上不可分解的Ｈａｒｉｓｈ－Ｃｈａｎｄｒａ模进行了完全分类，得到了与ｓｌ２（Ｃ）上模分类的不同形式．作为应用，又构造了实Ｖｉｒａｓｏｒｏ代数的一类新的不可约表示．     

正负Brocard点间的距离

定理　设三角形的Ｂｒｏｃａｒｄ角是θ,外接圆半径是Ｒ,则正负Ｂｒｏｃａｒｄ点间的距离是２Ｒ１－４ｓｉｎ２θ·ｓｉｎθ．引理１　将△ＡＢＣ绕外心Ｏ反时针旋转２θ得△Ａ１Ｂ１Ｃ１,则△ＡＢＣ的正Ｂｒｏｃａｒｄ点与△Ａ１Ｂ１Ｃ１的负Ｂｒｏｃａｒｄ点重合．图１证明　如图１,设Ｐ是△ＡＢＣ的正Ｂｒｏｃａｒｄ点,延长ＡＰ、ＢＰ、ＣＰ分别交外接圆Ｏ于Ｂ１、Ｃ１、Ａ１,连结Ａ１Ｂ１、Ｂ１Ｃ１、Ｃ１Ａ１．则　∠ＰＡ１Ｃ１＝∠ＰＢ１Ａ１＝∠ＰＣ１Ｂ１＝θ．可见Ｐ是△Ａ１Ｂ１Ｃ１的负Ｂｒｏｃａｒｄ点．又易证△ＡＢＣ≌…     

L2—cross—validation最近邻中位数估计的渐近最优性

本文研究固定设计点模型的最近邻中位数估计的光滑参数的选择问题。在一定的正则性条件下得到了Ｌ２－ｃｒｏｓｓ－ｖａｌｉｄａｔｉｏｎ最近邻中位数估计的渐近最优性。同时还得到了最近邻中位数估计的弱Ｂａｈａｄｕｒ表示。     

广义Chebyshev－Vandermonde方程组的快速算法与求逆公式

广义Ｃｈｅｂｙｓｈｅｖ－Ｖａｎｄｅｒｍｏｎｄｅ方程组的快速算法与求逆公式成礼智（国防科技大学）ＩＮＥＲＳＩＯＮＦＯＲＭＵＬＡＡＮＤＦＡＳＴＳＯＬＵＴＩＯＮＦＯＲＧＥＮＥＲＡＬＣＨＥＢＹＳＨＥＶ－ＶＡＮＤＥＲＭＯＮＤＥＥＱＵＡＴＩＯＮＳ￥ＣｈｅｎｇＬｉ...     

Bishop–Phelps–Bollobás property for bilinear forms on spaces of continuous functions

It is shown that the Bishop–Phelps–Bollobás theorem holds for bilinear forms on the complex \(C_0(L_1)\times C_0(L_2)\) for arbitrary locally compact topological Hausdorff spaces \(L_1\) and \(L_2\).     

VMO Spaces Associated with Operators with Gaussian Upper Bounds on Product Domains

In this paper, we extend the well-known result “the predual of Hardy space \(H^1\) is VMO” to the product setting, associated with differential operators. Let \(L_i\), \(i = 1, 2\), be the infinitesimal generators of the analytic semigroups \(\{e^{-tL_i}\}\) on \(L^2({\mathbb {R}})\). Assume that the kernels of the semigroups \(\{e^{-tL_i}\}\) satisfy the Gaussian upper bounds. We introduce the VMO spaces VMO\(_{L_1, L_2}(\mathbb {R}\times \mathbb {R})\) associated with operators \(L_1\) and \(L_2\) on the product domain \(\mathbb {R}\times \mathbb {R}\), then show that the dual space of VMO\(_{L_1, L_2}(\mathbb {R}\times \mathbb {R})\) is the Hardy space \(H^1_{L_1^*, L_2^*}(\mathbb {R}\times \mathbb {R})\) associated with the adjoint operators \(L^*_1\) and \(L^*_2\).     

Marcinkiewicz-Type Spectral Multipliers on Hardy and Lebesgue Spaces on Product Spaces of Homogeneous Type

Let \(X_1\) and \(X_2\) be metric spaces equipped with doubling measures and let \(L_1\) and \(L_2\) be nonnegative self-adjoint operators acting on \(L^2(X_1)\) and \(L^2(X_2)\) respectively. We study multivariable spectral multipliers \(F(L_1, L_2)\) acting on the Cartesian product of \(X_1\) and \(X_2\). Under the assumptions of the finite propagation speed property and Plancherel or Stein–Tomas restriction type estimates on the operators \(L_1\) and \(L_2\), we show that if a function F satisfies a Marcinkiewicz-type differential condition then the spectral multiplier operator \(F(L_1, L_2)\) is bounded from appropriate Hardy spaces to Lebesgue spaces on the product space \(X_1\times X_2\). We apply our results to the analysis of second-order elliptic operators in the product setting, specifically Riesz-transform-like operators and double Bochner–Riesz means.     

Asymptotics for the stationary distribution in a discrete-time two-dimensional quasi-birth-and-death process

We consider a discrete-time two-dimensional process $\{(L_{n}^{(1)},L_{n}^{(2)})\}$ on $\mathbb{Z}_{+}^{2}$ with a background process {J _n } on a finite set, where individual processes $\{L_{n}^{(1)}\}$ and $\{L_{n}^{(2)}\}$ are both skip free. We assume that the joint process $\{Y_{n}\}=\{(L_{n}^{(1)},L_{n}^{(2)},J_{n})\}$ is Markovian and that the transition probabilities of the two-dimensional process $\{(L_{n}^{(1)},L_{n}^{(2)})\}$ are modulated depending on the state of the background process {J _n }. This modulation is space homogeneous, but the transition probabilities in the inside of $\mathbb{Z}_{+}^{2}$ and those around the boundary faces may be different. We call this process a discrete-time two-dimensional quasi-birth-and-death (2D-QBD) process, and obtain the decay rates of the stationary distribution in the coordinate directions. We also distinguish the case where the stationary distribution asymptotically decays in the exact geometric form, in the coordinate directions.     

Motivic structures on higher homotopy groups of hyperplane arrangements

In this note, we show the existence of motivic structures on certain objects arising from the higher (rational) homotopy groups of non-nilpotent spaces. Examples of such spaces include several families of hyperplane arrangements. In particular, we construct an object in Nori’s category of motives whose realization is a certain completion of \(\pi _{n}({\mathbb P}^{n} {\setminus } \{L_{1}, \ldots , L_{n+2}\})\) where the \(L_{i}\) are hyperplanes in general position. Similar results are shown to hold in Vovoedsky’s setting of mixed motives.     

On Some Properties of Convolutions in Variable Exponent Lebesgue Spaces

A convolution in the variable exponent Lebesgue spaces \(L_{2\pi }^{p\left( \cdot \right) }\) is defined and its basic properties are investigated. It is also proved that this convolution can be approximated in \(L_{2\pi }^{p\left( \cdot \right) }\) by the finite linear combinations of Steklov means of the original function.     

Geometric ergodicity and the spectral gap of non-reversible Markov chains

We argue that the spectral theory of non-reversible Markov chains may often be more effectively cast within the framework of the naturally associated weighted-L _∞ space ${L_\infty^V}$ , instead of the usual Hilbert space L ₂?=?L ₂(π), where π is the invariant measure of the chain. This observation is, in part, based on the following results. A discrete-time Markov chain with values in a general state space is geometrically ergodic if and only if its transition kernel admits a spectral gap in ${L_\infty^V}$ . If the chain is reversible, the same equivalence holds with L ₂ in place of ${L_\infty^V}$ . In the absence of reversibility it fails: There are (necessarily non-reversible, geometrically ergodic) chains that admit a spectral gap in ${L_\infty^V}$ but not in L ₂. Moreover, if a chain admits a spectral gap in L ₂, then for any ${h\in L_2}$ there exists a Lyapunov function ${V_h\in L_1}$ such that V _h dominates h and the chain admits a spectral gap in ${L_\infty^{V_h}}$ . The relationship between the size of the spectral gap in ${L_\infty^V}$ or L ₂, and the rate at which the chain converges to equilibrium is also briefly discussed.     

The Hurwitz subgroups of $$E_6(2)$$

We prove that the exceptional group \(E_6(2)\) is not a Hurwitz group. In the course of proving this, we complete the classification up to conjugacy of all Hurwitz subgroups of \(E_6(2)\), in particular, those isomorphic to \(L_2(8)\) and \(L_3(2)\).     

On minimizers for the isotropic–nematic interface problem

In this paper, we investigate the structure and stability of the isotropic-nematic interface in 1-D. In the absence of the anisotropic energy, the uniaxial solution is the only global minimizer. In the presence of the anisotropic energy, the uniaxial solution with the homeotropic anchoring is stable for \(L_2<0\) and unstable for \(L_2>0\). We also present many interesting open questions, some of which are related to De Giorgi conjecture.