arXiv subjects
Publications and source records attributed to Viktor Losert.
We consider the measure algebra of a Chébli-\!Trimèche hypergroup (in particular, double coset spaces of classical Lie groups) and study the corresponding Arens products on its second dual. The behaviour turns out to be different to the group case investigated in [LNPS]. For this, we study more closely properties of the multiplication and generalized translation in a Chébli-\!Trimèche hypergroup and the asymptotic behaviour.
We study matrix coefficients of the unitary (and also the completely bounded) representations of SL(2;R) and its universal covering group. We describe the asymptotic distribution of column vectors in terms of Whittaker functions, exhibiting also a relationship to the Fourier transform.
For a connected Lie group G it was shown by Lee, Ludwig, Samei and Spronk that its Fourier algebra A(G) is weakly amenable only if G is abelian. We extend this result to general connected locally compact groups, extending an approach developed in special cases by Choi and Ghandehari.
Recently we have shown a structure theorem for locally compact groups of polynomial growth. We give now some applications on various growth functions and relations to FC-G - series. In addition, we show some results on related classes of groups.
We show that a compactly generated locally compact group of polynomial growth having no non-trivial compact normal subgroups can be embedded as a co-compact subgroup into a semidirect product of a connected, simply connected, nilpotent Lie group and a compact group. There is also a uniqueness statement for this extension.
For the Fourier Algebra of SL(2,R) any bounded multiplier is completely bounded.
For a discrete group G with Fourier algebra A(G), we study the topological centre $Z_t$ of the bidual. If G is amenable, then $Z_t$ = A(G). But if G contains a non-abelian free group $F_r$, we show that $Z_t$ is strictly larger than A(G). Furthermore, it is shown that the subalgebra of radial functions in A(G) is Arens regular.
The Ghahramani-Lau conjecture is established; in other words, the measure algebra of every locally compact group is strongly Arens irregular. To this end, we introduce and study certain new classes of measures (called approximately invariant, respectively, strongly singular) which are of interest in their own right. Moreover, we show that the same result holds for the measure algebra of any (not necessarily locally compact) Polish group.