Abstract
Extending M. Daws’ definition of ultra-amenable Banach algebras, we introduce the notion of operator ultra-amenability for completely contractive Banach algebras. For a locally compact group G, we show that the operator ultra-amenability of A(G) imposes severe restrictions on G. In particular, it forces G to be a discrete, amenable group with no infinite abelian subgroups. For various classes of such groups, this means that G is finite.
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B. E. Forrest: Research supported by NSERC.
V. Runde: Research supported by NSERC.
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Forrest, B.E., Runde, V. & Schlitt, K. Operator ultra-amenability. Arch. Math. 108, 465–471 (2017). https://doi.org/10.1007/s00013-016-1012-1
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DOI: https://doi.org/10.1007/s00013-016-1012-1