Sur l'analyse harmonique du groupe affine de la droite
Les propriétés des éléments analytiques sur une partie d’un corps ultramétrique complet, algébriquement clos, dépendent de l’existence sur de filtres strictement annulateurs que l’on caractérise par des relations arithmétiques entre les diamètres et les distances mutuelles des trous de grâce à la notion de -filtre. Alors les ensembles analytiques sont les ensembles sans -filtre à plage non vide. D’autre part, le problème de la transformation de Fourier -adique se ramène à un problème d’analycité...
This is a sequel to our recent work (2012) on the Fourier-Stieltjes algebra B(G) of a topological group G. We introduce the unitary closure G̅ of G and use it to study the Fourier algebra A(G) of G. We also study operator amenability and fixed point property as well as other related geometric properties for A(G).
Let G be a locally compact group, K a compact subgroup of G and A(G/K) the Fourier algebra of the coset space G/K. Applying results from [E. Kaniuth, Weak spectral synthesis in commutative Banach algebras, J. Funct. Anal. 254 (2008), 987-1002], we establish injection and localization theorems relating weak spectral sets and weak Ditkin sets for A(G/K) to such sets for A(H/H ∩ K), where H is a closed subgroup of G. We also prove some results towards the analogue of Malliavin's theorem for weak spectral...
It is shown that if G is a weakly amenable unimodular group then the Banach algebra , where is the Figà-Talamanca-Herz Banach algebra of G, is a dual Banach space with the Radon-Nikodym property if 1 ≤ r ≤ max(p,p’). This does not hold if p = 2 and r > 2.