scholarly journals L-ideals of M(G) determined by continuity of translation

1973 ◽  
Vol 18 (4) ◽  
pp. 307-316 ◽  
Author(s):  
Gavin Brown ◽  
William Moran
Keyword(s):  
Abelian Group ◽  
Locally Compact Abelian Group ◽  
Norm Topology ◽  
Locally Compact ◽  
Total Variation Norm ◽  
Absolutely Continuous ◽  
Convolution Algebra ◽  
Borel Measures ◽  
Variation Norm ◽  
Stieltjes Transforms

G denotes a locally compact abelian group and M(G) the convolution algebra of regular bounded Borel measures on G. An ideal I of M(G) closed in the usual (total variation) norm topology is called an L-ideal if μ ∈ I, ν≪ μ (ν absolutely continuous with respect to μ) implies that ν ∈ I. Here we are concerned with the L-idealsL1(G), , and M0(G) where, as usual, L1(G) denotes the set of measures absolutely continuous with respect to Haar measure, denotes the radical of L1(G) in M(G) and M0(G) denotes the set of measures whose Fourier-Stieltjes transforms vanish at infinity.

Uniform approximation by Fourier–Stieltjes transforms

1968 ◽  
Vol 64 (2) ◽  
pp. 323-333 ◽  
Author(s):  
Donald E. Ramirez
Keyword(s):  
Abelian Group ◽  
Compact Abelian Group ◽  
Continuous Functions ◽  
Dual Group ◽  
Locally Compact Abelian Group ◽  
Norm Topology ◽  
Locally Compact ◽  
Borel Measures ◽  
Bounded Functions ◽  
Stieltjes Transforms

Let G be a locally compact Abelian group; Γ the dual group of G; CB(Γ) the algebra of continuous, bounded functions on Γ C0(Γ) the algebra of continuous functions on Γ which vanish at infinity; M(G) the algebra of bounded Borel measures on G; M(G)^ the algebra of Fourier–Stieltjes transforms; and M(G)^− the completion of M(G)^ in the sup-norm topology on Γ. The object of this paper is to study the natural pairing between M(G)^ and M(Γ).

scholarly journals Fourier-Stieltjes Transforms which vanish at infinity off certain sets

1978 ◽  
Vol 19 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Louis Pigno
Keyword(s):  
Abelian Group ◽  
Haar Measure ◽  
Compact Abelian Group ◽  
Measure Zero ◽  
Absolutely Continuous ◽  
Character Group ◽  
Convolution Algebra ◽  
Borel Measures ◽  
Discrete Measures ◽  
Stieltjes Transforms

In this paper G is a nondiscrete compact abelian group with character group Г and M(G) the usual convolution algebra of Borel measures on G. We designate the following subspaces of M(G) employing the customary notations: Ma(G) those measures which are absolutely continuous with respect to Haar measure; MS(G) the space of measures concentrated on sets of Haar measure zero and Md(G) the discrete measures.

scholarly journals A Theorem on Algebras of Measures on Topological Groups

1959 ◽  
Vol 11 (4) ◽  
pp. 195-206 ◽  
Author(s):  
J. H. Williamson
Keyword(s):  
Banach Space ◽  
Abelian Group ◽  
Compact Abelian Group ◽  
Locally Compact Abelian Group ◽  
Topological Groups ◽  
Finite Sets ◽  
Locally Compact ◽  
Borel Measures ◽  
Bounded Complex ◽  
Image Position

Let G be a locally compact Abelian group, and the set of bounded complex (regular countably-additive Borel) measures on G. It is well known that becomes a Banach space if the norm is defined bythe supremum being over all finite sets of disjoint Borel subsets of G.

Large families of singular measures having absolutely continuous convolution squares

1968 ◽  
Vol 64 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Karl Stromberg
Keyword(s):  
Abelian Group ◽  
Compact Abelian Group ◽  
Locally Compact Abelian Group ◽  
Measure Algebra ◽  
Regular Measure ◽  
Locally Compact ◽  
Absolutely Continuous ◽  
Singular Measures ◽  
Large Families ◽  
Nikodym Derivative

In 1966, Hewitt and Zuckerman(3,4) proved that if G is a non-discrete locally compact Abelian group with Haar measure λ, then there exists a non-negative, continuous regular measure μon G that is singular to λ(μ ┴ λ) such that μ(G)= 1, μ * μ is absolutely continuous with respect to λ(μ * μ ≪ λ), and the Lebesgue-Radon-Nikodym derivative of μ * μ with respect to λ is in (G, λ) for all real p > 1. They showed also that such a μ can be chosen so that the support of μ * μ contains any preassigned σ-compact subset of G. It is the purpose of the present paper to extend this result to obtain large independent sets of such measures. Among other things the present results show that, for such groups, the radical of the measure algebra modulo the -algebra has large dimension. This answers a question (6.4) left open in (3).

A characterization of quotient algebras of Ll(G)

1969 ◽  
Vol 66 (3) ◽  
pp. 547-551 ◽  
Author(s):  
Donald E. Ramirez
Keyword(s):  
Continuous Functions ◽  
Dual Group ◽  
Locally Compact Abelian Group ◽  
Absolutely Continuous ◽  
Borel Measures ◽  
Bounded Functions ◽  
Continuous Measures ◽  
Stieltjes Transforms ◽  
Absolutely Continuous Measures

Let G be a locally compact Abelian group; Γ the dual group of G; C0(Γ) the algebra of continuous functions on Γ which vanish at infinity; CB(Γ) the continuous, bounded functions on Γ; M (G) the algebra of bounded Borel measures on G; L1(G) the algebra of absolutely continuous measures; and M(G)∩ the algebra of Fourier–Stieltjes transforms.

Translates of L∞ functions and of bounded measures

1964 ◽  
Vol 4 (4) ◽  
pp. 403-409 ◽  
Author(s):  
R. E. Edwards
Keyword(s):  
Abelian Group ◽  
Continuous Functions ◽  
Group Element ◽  
Locally Compact Abelian Group ◽  
Space Of Continuous Functions ◽  
Locally Compact ◽  
Absolutely Continuous ◽  
Radon Measures ◽  
Uniformly Continuous Function ◽  
Uniformly Continuous

D. A. Edwards has shown [1] that if X is a locally compact Abelian group and f ∈ L∞, then the translate fa of f varies continuously with α if and only if f is (equal l.a.e. to) a bounded, uniformly continuous function. He remarks that this is a sort of dual to part of a result due to Plessner and Raikov which asserts that an element μ of the space Mb of bounded Radon measures on X belongs to L1 (i.e., is absolutely continuous relative to Haar measure) if and only its translates vary continuously with the group element, the relevant topology on Mb being that defined by the natural norm of Mb as the dual of the space of continuous functions vanishing at infinity. The proof he uses (ascribed to Reiter) applies equally well in both cases, and also to the case in which X is non-Abelian. A brief examination shows that in the latter case it is ultimately immaterial whether left- or right-translates are considered; since the extra complexities of this case are principally terminological, we shall direct no further attention to it.

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