算子fsamjer不等式的反转

IF 0.4 4区 数学 Q4 MATHEMATICS
S. Dragomir
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引用次数: 8

摘要

让 $f$ 是上的算子凸函数 $I$ 和 $A,$ $B\in \mathcal{SA}_{I}\left( H\right) ,$ 具有谱的自伴随算子的凸集 $I.$ 如果 $A\neq B$ 和 $f,$ 作为一个算子函数,在 \begin{equation*} [ A,B] :=\left\{ ( 1-t) A+tB \mid t\in [ 0,1] \right\} \,, \end{equation*} 同时 $p:[ 0,1] \rightarrow \lbrack 0,\infty )$ 勒贝格是否是可积对称的,即 $p\left( 1-t\right) $ $=p\left( t\right) $ 对所有人 $t\in [ 0,1] ,$ 然后 \begin{align*} 0& \leq \int_{0}^{1}p\left( t\right) f\left( \left( 1-t\right) A+tB\right) dt-\left( \int_{0}^{1}p\left( t\right) dt\right) f\left( \frac{A+B}{2}\right) \\ & \leq \frac{1}{2}\left( \int_{0}^{1}\left\vert t-\frac{1}{2}\right\vert p\left( t\right) dt\right) \left[ \nabla f_{B}\left( B-A\right) -\nabla f_{A}\left( B-A\right) \right] \end{align*} 和 \begin{align*} 0& \leq \left( \int_{0}^{1}p\left( t\right) dt\right) \frac{f\left( A\right) +f\left( B\right) }{2}-\int_{0}^{1}p\left( t\right) f\left( \left( 1-t\right) A+tB\right) dt \\ & \leq \frac{1}{2}\int_{0}^{1}\left( \frac{1}{2}-\left\vert t-\frac{1}{2} \right\vert \right) p\left( t\right) dt\left[ \nabla f_{B}\left( B-A\right) -\nabla f_{A}\left( B-A\right) \right] \,. \end{align*} 还给出了两个特别有趣的例子。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Reverses of Operator Féjer's Inequalities
Let $f$ be an operator convex function on $I$ and $A,$ $B\in \mathcal{SA}_{I}\left( H\right) ,$ the convex set of selfadjoint operators with spectra in $I.$ If $A\neq B$ and $f,$ as an operator function, is G\^{a}teaux differentiable on \begin{equation*} [ A,B] :=\left\{ ( 1-t) A+tB \mid t\in [ 0,1] \right\} \,, \end{equation*} while $p:[ 0,1] \rightarrow \lbrack 0,\infty )$ is Lebesgue integrable and symmetric, namely $p\left( 1-t\right) $ $=p\left( t\right) $ for all $t\in [ 0,1] ,$ then \begin{align*} 0& \leq \int_{0}^{1}p\left( t\right) f\left( \left( 1-t\right) A+tB\right) dt-\left( \int_{0}^{1}p\left( t\right) dt\right) f\left( \frac{A+B}{2}\right) \\ & \leq \frac{1}{2}\left( \int_{0}^{1}\left\vert t-\frac{1}{2}\right\vert p\left( t\right) dt\right) \left[ \nabla f_{B}\left( B-A\right) -\nabla f_{A}\left( B-A\right) \right] \end{align*} and \begin{align*} 0& \leq \left( \int_{0}^{1}p\left( t\right) dt\right) \frac{f\left( A\right) +f\left( B\right) }{2}-\int_{0}^{1}p\left( t\right) f\left( \left( 1-t\right) A+tB\right) dt \\ & \leq \frac{1}{2}\int_{0}^{1}\left( \frac{1}{2}-\left\vert t-\frac{1}{2} \right\vert \right) p\left( t\right) dt\left[ \nabla f_{B}\left( B-A\right) -\nabla f_{A}\left( B-A\right) \right] \,. \end{align*} Two particular examples of interest are also given.
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来源期刊
CiteScore
0.70
自引率
16.70%
发文量
27
审稿时长
>12 weeks
期刊介绍: The Tokyo Journal of Mathematics was founded in 1978 with the financial support of six institutions in the Tokyo area: Gakushuin University, Keio University, Sophia University, Tokyo Metropolitan University, Tsuda College, and Waseda University. In 2000 Chuo University and Meiji University, in 2005 Tokai University, and in 2013 Tokyo University of Science, joined as supporting institutions.
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