关于多元Szaesz—Mirakjan算子的加权逼近

本文主要讨论一类二元Ｓｚａｅｓｚ－Ｍｉｒａｋｊａｎ算子的加权逼近问题，我们首先指出了在通常的加权范数下它是无界的，然后我们给出了一类新的加权范数，在此范数下，它是有界的，最后利用一类多元Ｋ－泛函与多元分解技巧，我们给出了二元Ｓｚａｅｓｚ－Ｍｉｒａｋｊａｎ算子加权逼近的特征刻划。     

关于Szasz—Kantorovich算子的强逆不等式

本文对Ｓｚａｓｚ－Ｋａｎｔｏｒｏｖｉｃｈ算子Ｓｎ＾＊（ｆ，ｘ）证明了，当１〈ｐ≤∝时存在某一正整数ｍ，使得ｗψ＾２（ｆ；１／√ｎ）ｐ≤Ｍ（‖Ｓｎ＾＊（ｆ，ｘ）－ｆ‖ｐ＋‖Ｓｍｍ＾＊（ｆ，ｘ）－ｆ‖ｐ），ψ（ｘ）＾２＝ｘ，Ｍ〉０，ｗψ＾（ｆ，ｔ）ｐ为Ｄｉｔｚａｉｎ和Ｔｏｔｉｋ光滑模〔２〕。     

Approximation by modified Szasz—Mirakjan operators on weighted spaces

The theorems on weighted approximation and the order of approximation of continuous functions by modified Szasz—Mirakjan operators on all positive semi-axis are established.     

一类修正的Szasz—Kantorvich算子与Baskakov—Kantorovich算子的逼近定理

该文利用三对角无穷方阵修正Ｓｚａｓｚ－Ｋａｎｔｏｒｖｉｃｈ（以下简记Ｓ－Ｋ）算子与Ｂａｓｋａｋｏｖ－Ｋａｎｔｏｒｏｖｉｃｈ（以下简记Ｂ－Ｋ）算子。对于这两类修正的算子，我们得到了Ｈ．Ｈｅｒｅｎｓ和Ｇ．Ｇ．Ｌｏｒｅｅｎｔｚ型的结果以及在Ｌｐ（０）中逼近的正逆定理。     

Szasz型算子同时逼近的点态结果

本文给出了Ｓｚａｓｚ－ｉｒａｋｊａｎ算子和Ｓｚａｓｚ－Ｋａｎｔｏｒｏｖｉｃｈ算子组合的同时逼近的点态结果，并用其导数给出了高阶Ｌｉｐｓｃｈｉｔｚ函数类的特征刻划。     

Operator Matrix Forms of Positive Operators

If a 3-tuple (A:H1→H1,B:H2→H1,C:H2→H2）of operators on Hibert spaces is given,we proved that the operator ～↑A:=(↑A ↓B^*↑B ↓C) on H=H1 H2 is ≥0 is and only if A≥0,R(B)∪→R（A^1/2) and C≥B^* A^ b,where A^ is the generalized inverse of A.In general,A^ is a closed operator,but since R(B)∪→R(A^1/2,B^* A^ B is bounded yet.     

二维Szasz—Durrmeyer算子在C空间的逼近定理

本文在Ｓ＝｛（ｘ，ｙ）│０〈ｘ〈＋∞，ｘ≤ｙ〈＋∞｝上定义了一个二维的Ｓｚａｓｚ－Ｄｕｒｒｍｅｙｅｒ算子，并给出了该算子在Ｃ空间上的逼近等价定理。     

Generalized Szász-Mirakjan Operator Approximation

In this paper we shall defin a kind of generahzed Szász-Mirakjan operator and discussits convergence and degree of approximation,extend some results got by J.Grof and Z.Ditzian.     

On Weighted Estimates of High-Order Riesz-Bessel Transformations Generated by the Generalized Shift Operator

In this paper, we establish sufficient conditions on weights which ensure that high-order Riesz-Bessel transformations generated by the generalized shift operator act boundedly from one weighted Lp-space into another.     

多元Bernstein—Durrmeyer算子的正逆定理

本文给出单形Ｓ上多元Ｂｅｒｎｓｔｅｉｎ－Ｄｕｒｒｍｅｙｅｒ算子在连续函数空间Ｃ（Ｓ）的强型正定理的积分型估计式弱型逆定理从而建立了算子逼近特征刻划等价定理。     

一类修正的Szasz－Kantorvich算子与Baskakov－Kantorovich算子的逼近定理

该文利用三对角无穷方阵修正Ｓｚａｓｚ－Ｋａｎｔｏｒｖｉｃｈ（以下简记Ｓ－Ｋ）算子与Ｂａｓｋａｋｏｖ－Ｋａｎｔｏｒｏｖｉｃｈ（以下简记Ｂ－Ｋ）算子．对于这两类修正的算子，我们得到了Ｈ．Ｈｅｒｅｎｓ和Ｇ．Ｇ．Ｌｏｒｅｎｔｚ型的结果以及在Ｌｐ（０）中逼近的正逆定理。     

Pointwise Simultaneous Approximation by Combinations of Baskakov Operators

In this paper, we investigate the relation between the rate of convergence for the derivatives of the combinations of Baskakov operators and the smoothness for the derivatives of the functions approximated. We give some direct and inverse results on pointwise simultaneous approximation by the combinations of Baskakov operators. We also give a new equivalent result on pointwise approximation by these operators.     

单纯形上Meyer—Konig—Zeller算子及其逼近定理

本文构造单纯形Ｔ＝｛（ｘ，ｙ）：ｘ，ｙ≥０，ｘ＋ｙ≤１｝上的Ｍｅｙｅｒ－Ｋｏｎｉｇ－Ｚｅｌｌｅｒ算子，并且讨论它的逼近性质。     

On The Order of Weyl—Heisenburg Wavelet Approximation

The order of a concrete Weyl-Heisenburing wavelet approximation is given.This order isshown to be optimal.     

Bernstein—Sikkema算子的正逆定理

本文给出了Ｂｅｒｎｓｔｅｉｎ－Ｓｉｋｋｅｍａ算子的一个积分型估计式以及一个弱性逆定理。     

Generalized Inverses of Matrices over Rings

Let R be a ring, * be an involutory function of the set of all finite matrices over R. In this paper, necessary and sufficient conditions are given for a matrix to have a (1,3)-inverse, (1,4)-inverse, or Moore-P enrose inverse, relative to *. Some results about generalized inverses of matrices over division rings are generalized and improved.     

The Spirallike Mapping of Type α and the Generalized Roper-Suffridge Operator

In this paper, we get the fact that generalized Roper-Suffridge operators act on spirallike mapping of type α on different domains is invariable, these results include some results known.     

The Degree Theory of a New Operator

§１．　ＩｎｔｒｏｄｕｃｔｉｏｎＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔｔｈｅｄｅｇｒｅｅｔｈｅｏｒｙｆｏｒａｋ－ｓｅｔ－ｃｏｎｔｒａｃｔｏｐｅｒａｔｏｒｈａｓｍａｎｙａｐｐｌｉｃａｔｉｏｎｓｏｎｔｈｅｅｘｉｓｔｅｎｃｅｏｆｔｈｅｓｏｌｕｔｉｏｎｓｏｆｓｏｍｅｅｑｕａｔｉｏｎｓ（ｓｅｅ［１］，［２］，［３］）．Ｈｏｗｅｖｅｒ，ｓｏｍｅｏｐｅｒａ－ｔｏｒｓａｒｅｎｏｔｋ－ｓｅｔ－ｃｏｎｔｒａｃｔｏｐｅｒａｔｏｒｓ．Ｉｔｉｓａｎｅｗｐｒｏｂｌｅｍｔｈａｔｗｅｅｓｔａｂｌｉｓｈａｄｅｇｒｅｅｔｈｅｏｒｙｆｏ…