On a class of convolution algebras of functions
Feichtinger, Hans G.
Annales de l'Institut Fourier, Tome 27 (1977), p. 135-162 / Harvested from Numdam
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Les espaces de Banach Λ(A,B,X,G) définis dans cette note sont des sous-espaces de L 1 (G) (G étant un groupe localement compact). Ils contiennent essentiellement des éléments de L 1 (G) qui peuvent dans un certain sens être bien approchés par des fonctions à support compact. Le résultat principal est le fait que Λ(A,B,X,G) est souvent une algèbre de Banach avec convolution comme multiplication. Il existe un grand nombre d’exemples très naturels. On démontre quelques théorèmes concernant la structure de ces espaces. Entre autre on donne des conditions simples qui impliquent l’existence des unités approchées ou la densité de K(G) dans Λ(A,B,X,G). Dans ce dernier cas on peut caractériser les idéaux fermés.

The Banach spaces Λ(A,B,X,G) defined in this paper consist essentially of those elements of L 1 (G) (G being a locally compact group) which can in a certain sense be well approximated by functions with compact support. The main result of this paper is the fact that in many cases Λ(A,B,X,G) becomes a Banach convolution algebra. There exist many natural examples. Furthermore some theorems concerning inclusion results and the structure of these spaces are given. In particular we prove that simple conditions imply the existence of left approximate units or the density of K(G). In the latter case a characterization of the closed left ideals is possible.

@article{AIF_1977__27_3_135_0,
     author = {Feichtinger, Hans G.},
     title = {On a class of convolution algebras of functions},
     journal = {Annales de l'Institut Fourier},
     volume = {27},
     year = {1977},
     pages = {135-162},
     doi = {10.5802/aif.665},
     mrnumber = {57 \#10358},
     zbl = {0316.43004},
     language = {en},
     url = {http://dml.mathdoc.fr/item/AIF_1977__27_3_135_0}
}

Feichtinger, Hans G. On a class of convolution algebras of functions. Annales de l'Institut Fourier, Tome 27 (1977) pp. 135-162. doi : 10.5802/aif.665. http://gdmltest.u-ga.fr/item/AIF_1977__27_3_135_0/

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