Asymmetric maximal ideals in 𝑀(𝐺)

Author:

Saeki Sadahiro

Abstract

Let G be a nondiscrete LCA group, M ( G ) M(G) the measure algebra of G, and M 0 ( G ) {M_0}(G) the closed ideal of those measures in M ( G ) M(G) whose Fourier transforms vanish at infinity. Let Δ G , Σ G {\Delta _G},{\Sigma _G} and Δ 0 {\Delta _0} be the spectrum of M ( G ) M(G) , the set of all symmetric elements of Δ G {\Delta _G} , and the spectrum of M 0 ( G ) {M_0}(G) , respectively. In this paper this is shown: Let Φ \Phi be a separable subset of M ( G ) M(G) . Then there exist a probability measure τ \tau in M 0 ( G ) {M_0}(G) and a compact subset X of Δ 0 Σ G {\Delta _0}\backslash {\Sigma _G} such that for each | c | 1 |c| \leqslant 1 and each \[ ν Φ Card { f X : τ ^ ( f ) = c and | ν ^ ( f ) | = r ( ν ) } 2 c . \nu \in \Phi \;{\text {Card}}\;\{ f \in X:\hat \tau (f) = c\;{\text {and}}\;|\hat \nu (f)| = r(\nu )\} \geqslant {2^{\text {c}}}. \] Here r ( ν ) = sup { | ν ^ ( f ) | : f Δ G G ^ } r(\nu ) = \sup \{ |\hat \nu (f)|:f \in {\Delta _G}\backslash \hat G\} . As immediate consequences of this result, we have (a) every boundary for M 0 ( G ) {M_0}(G) is a boundary for M ( G ) M(G) (a result due to Brown and Moran), (b) Δ G Σ G {\Delta _G}\backslash {\Sigma _G} is dense in Δ G G ^ {\Delta _G}\backslash \hat G , (c) the set of all peak points for M ( G ) M(G) is G ^ \hat G if G is σ \sigma -compact and is empty otherwise, and (d) for each μ M ( G ) \mu \in M(G) the set μ ^ ( Δ 0 Σ G ) \hat \mu ({\Delta _0}\backslash {\Sigma _G}) contains the topological boundary of μ ^ ( Δ G G ^ ) \hat \mu ({\Delta _G}\backslash \hat G) in the complex plane.

Publisher

American Mathematical Society (AMS)

Subject

Applied Mathematics,General Mathematics

Reference15 articles.

1. 𝑀₀(𝐺) has a symmetric maximal ideal off the Šilov boundary;Brown, Gavin;Proc. London Math. Soc. (3),1973

2. 𝐿^{1/2}(𝐺) is the kernel of the asymmetric maximal ideals of 𝑀(𝐺);Brown, Gavin;Bull. London Math. Soc.,1973

3. 𝑀_{𝑂}(𝐺)-boundaries are 𝑀(𝐺)-boundaries;Brown, Gavin;J. Functional Analysis,1975

4. Measures vanishing off the symmetric maximal ideals of 𝑀(𝐺);Graham, Colin C.;Proc. Cambridge Philos. Soc.,1974

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3