首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Greedy wavelet projections are bounded on BV
Authors:Pawel Bechler  Ronald DeVore  Anna Kamont  Guergana Petrova  Przemyslaw Wojtaszczyk
Institution:Institute of Mathematics, Polish Academy of Sciences, ul. Sniadeckich 8, 00-950 Warsaw, Poland ; Department of Mathematics, University of South Carolina, Columbia, South Carolina 29208 ; Institute of Mathematics, Polish Academy of Sciences, Branch in Gdansk, ul. Abrahama 18, 81-825 Sopot, Poland ; Department of Mathematics, Texas A&M University, College Station, Texas 77843 ; Institute of Applied Mathematics and Mechanics, Warsaw University, ul. Banacha 2, 02-097 Warsaw, Poland
Abstract:Let $ \mathrm{BV}=\mathrm{BV}(\mathbb{R}^d)$ be the space of functions of bounded variation on $ \mathbb{R}^d$ with $ d\ge 2$. Let $ \psi_\lambda$, $ \lambda\in\Delta$, be a wavelet system of compactly supported functions normalized in $ \mathrm{BV}$, i.e., $ \vert\psi_\lambda\vert _{\mathrm{BV}(\mathbb{R}^d)}=1$, $ \lambda\in\Delta$. Each $ f\in \mathrm{BV}$ has a unique wavelet expansion $ \sum_{\lambda\in\Delta} c_\lambda(f)\psi_\lambda$ with convergence in $ L_1(\mathbb{R}^d)$. If $ \Lambda_N(f)$ is the set of $ N$ indicies $ \lambda\in\Delta$ for which $ \vert c_\lambda(f)\vert$ are largest (with ties handled in an arbitrary way), then $ \mathcal{G}_N(f):=\sum_{\lambda\in\Lambda_N(f)}c_\lambda(f)\psi_\lambda$ is called a greedy approximation to $ f$. It is shown that $ \vert\mathcal{G}_N(f)\vert _{\mathrm{BV}(\mathbb{R}^d)}\le C\vert f\vert _{\mathrm{BV}(\mathbb{R}^d)}$ with $ C$ a constant independent of $ f$. This answers in the affirmative a conjecture of Meyer (2001).

Keywords:$N$-term approximation  greedy approximation  functions of bounded variation  thresholding  bounded projections
点击此处可从《Transactions of the American Mathematical Society》浏览原始摘要信息
点击此处可从《Transactions of the American Mathematical Society》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号