English

Ideals in CB(X) arising from ideals in X

Functional Analysis 2016-06-08 v2

Abstract

Let XX be a completely regular topological space. We assign to each (set theoretic) ideal of XX an (algebraic) ideal of CB(X)C_B(X), the normed algebra of continuous bounded complex valued mappings on XX equipped with the supremum norm. We then prove several representation theorems for the assigned ideals of CB(X)C_B(X). This is done by associating a certain subspace of the Stone--\v{C}ech compactification βX\beta X of XX to each ideal of XX. This subspace of βX\beta X has a simple representation, and in the case when the assigned ideal of CB(X)C_B(X) is closed, coincides with its spectrum as a CC^*-subalgebra of CB(X)C_B(X). This in particular provides information about the spectrum of those closed ideals of CB(X)C_B(X) which have such representations. This includes the non-vanishing closed ideals of CB(X)C_B(X) whose spectrums are studied in great detail. Our representation theorems help to understand the structure of certain ideals of CB(X)C_B(X). This has been illustrated by means of various examples. Our approach throughout will be quite topological and makes use of the theory of the Stone--\v{C}ech compactification.

Keywords

Cite

@article{arxiv.1508.07734,
  title  = {Ideals in CB(X) arising from ideals in X},
  author = {M. R. Koushesh},
  journal= {arXiv preprint arXiv:1508.07734},
  year   = {2016}
}

Comments

61 pages. This article contains (and extends) most theorems in arXiv:1302.2235

R2 v1 2026-06-22T10:45:00.286Z