关于拟微分算子有界性定理的改进形式

Calderon A. P. et al. were studied a class of the bounded pseudo-differential-operators of order -M and type ρ,δ₁, δ₂, and showed them to be bounded in L² provided that 0≤ρ≤δ₁<1, 0≤ρ≤δ₂<1 and M/n≥1/2(δ₁+δ₂)-ρ. H?raander et al. have shown that if the aforecited conditions are not valid, then the conclusion that A is bounded in L² isn't necessarily right. Calderon et al. settled the borderline case and remove the restriction on the support of a.     

p-值星形函数的子类

Let M_n+p-1 denote the class of functions f(z) = 1/z^p+a₀/z^p-2+a₁/z^p-2+…+a_n+p-1zⁿ+…, regular and p-valent in the annulus 0<|z|<1 and satisfying Re((D^n+p f(z))/(D^n+p-1 f(z)))-2)<-(n+p-1)/(n+p),|z|<1,n>-p where D^n+p-1 f(z)=1/z^p((z^n+2p-1f(z))/(n+p-1)!)^(n+p-1).M_n+p?M_n+p-1 is proved. Since M₀ is the subclass of p-valent meromorphically starlike functions, all functions in Mn + p-1 are p-valent meromorphically star-like functions. Further the integrals of functions in M_n+p-1, are considered.     

一些多项式型的有限维对合系

In this paper, starting from the combination of two in volutive systems, we consider separately some systems of polynomial functions:{I_m⁽¹⁾=B_m+R_m}_m=0^∞, {I_m⁽²⁾=B_m+S_m}_m=0^∞, {I_m⁽³⁾=B_m+T_m}_m=0^∞ and so on; and analyse carefully the sufft cient and necessary conditions of the involution of three systems of functions {I_m⁽ⁱ⁾}_m=0^∞(1≤i≤3) with general coefficients.Furthermore,we present concrete forms of the involutive systems hidden in {I_m⁽ⁱ⁾}_m=0^∞(1≤i≤3);and thus obtain six kinds of nontrivial involutive systems of functions, which include a few involutive systems discussed inthe literature. Based upon these involutive systems, we can generate a lot of new finite-dimensional Hamiltonian systems which are completely integrable in the sense of Liouville.     

一类有限阶可解完全群

It has been shown in the present paper that the automorphism group of the group of upper triangular matrices (a_ij) with entries in the finite field F_q(q=p^m,q>2, P is prime) and with α₁₁=1 is solvable and complete.     

Long-time Asymptotic Behavior for the Derivative Schr¨odinger Equation with Finite Density Type Initial Data*

In this paper, the authors apply ? steepest descent method to study the Cauchy problem for the derivative nonlinear Schr¨odinger equation with finite density type initial data iq_t + q_xx + i(|q|²q)x = 0,q(x, 0) = q0(x),where lim/x→±∞ q0(x) = q± and |q±| = 1. Based on the spectral analysis of the Lax pair,they express the solution of the derivative Schr¨odinger equation in terms of solutions of a Riemann-Hilbert problem. They compute the long time asymptotic expansion of the solution q(x, t) in different space-time regions. For the region ξ =x/t with |ξ + 2| < 1, the long time asymptotic is given by q(x, t) = T (∞)^?2q^r_Λ(x, t) + O(t^?3/4 ),in which the leading term is N(I) solitons, the second term is a residual error from a ? equation. For the region |ξ + 2| > 1, the long time asymptotic is given by q(x, t) = T (∞)^?2q^r_Λ(x, t) ? t^?1/2 if¹¹ + O(t^?3/4 ),in which the leading term is N(I) solitons, the second t^?1/2 order term is soliton-radiation interactions and the third term is a residual error from a ? equation. These results are verification of the soliton resolution conjecture for the derivative Schr¨odinger equation. In their case of finite density type initial data, the phase function θ(z) is more complicated that in finite mass initial data. Moreover, two triangular decompositions of the jump matrix are used to open jump lines on the whole real axis and imaginary axis, respectively.     

一类拟线性椭圆方程组的Dirichlet问题

The homogeneous Dirichlet problem(1) for quasilinear elliptic system in a bounded domain Ω is investigated in this paper. The existence of generalized solutions in [H₀¹(Ω)]^N is obtained by using the contructive Galerkin method. For the case of a_ij^lm=0 when i≠j, it is estatablished that such generalized solutions have bounded [L_∞(Ω)]N norm and possess Holeler continuity. Even in the particular case that f_i are independent of Du, our results have improved those of A. V. Lair [Ann. Mat. Pura Appl., 116(1978)], allowing b_i¹(x,u) and f_i(x,u) to have a growth in u arbitrarily close to 1.     

关于组合合成阵

We define the r^th combinatorial compound C_r^*(A) of a matrix A, which can be viewed as the characteristic function of the subset of the rxr submatrices of A which are combinatorially nonsingular. We prove that for 1≤rr^*(A)is. We determine the minimum number of 2×2 and 3×3 combinatorially nonsingular submatrices over all n×n fully indecomposable matrices and make a jecture for general r.     

Picard-Type Theorem and Curvature Estimate on an Open Riemann Surface with Ramification*

Let M be an open Riemann surface and G : M → Pⁿ(C) be a holomorphic map. Consider the conformal metric on M which is given by ds² = k e Gk^2m|ω|², where eG is a reduced representation of G, ω is a holomorphic 1-form on M and m is a positive integer. Assume that ds² is complete and G is k-nondegenerate(0 ≤ k ≤ n). If there are q hyperplanes H₁, H₂, · · · , H_q Pⁿ(C) located in general position such that G is ramified over H_j with multiplicity at least γ_j (> k) for each j ∈ {1, 2, · · · , q}, and it holds that Xj=1 1 -k/γ_j> (2n - k + 1) （mk/2+ 1）,then M is flat, or equivalently, G is a constant map. Moreover, one further give a curvature estimate on M without assuming the completeness of the surface.     

二值回归模型中自变量误差的处理

In this paper the binary regression model, in which the response Y is binary, i.e. Y takes the value 0 or 1 only, is considered. The conditional probability P{Y=1|X=x} is assumed to be of the form G(a₀+a₁x), where x is the measurement of the factor, a= (a₀,a₁)′ is the vector of the unknown parameter being estimated and G(a) = (1+e^a)^-1. The measurement x is assu-med to be contaminated when the value of x is out of certain limit. M-estimation is employed to estimate the unknown a of the model. In this paper, the consistent M-estimation is proved to be asymptotically normal and the optimal M-equation is obtained. Finally, a computation method is introduced to solve the M-equation and to get the optimal solution.     

矩阵指数的偏迹不等式

In this paper it is shown that if C is an n×n complex matrix and C^(k) is the k-th compound of C, 1≤k≤n, N = (n k) and if the eigenvalues of C^(k) are labeled inorder of decreasing magnitude |λ₁(C^(k))|≥λ₂(C^(k))|≥…≥λ_N(C^(k))|define the partial trace tr_i^(k)(C) by (?) Then for two n×n Hermrtian matrices A, B,with equality holds if A, B are commutative or k = n.