Abstract.
Let G be a locally compact group. We show that its Fourier algebra A(G) is amenable if and only if G has an abelian subgroup of finite index, and that its Fourier–Stieltjes algebra B(G) is amenable if and only if G has a compact, abelian subgroup of finite index. We then show that A(G) is weakly amenable if the component of the identity of G is abelian, and we prove some partial results towards the converse.
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Albrecht, E., Dales, H. G.: Continuity of homomorphisms from C*-algebras and other Banach algebras. In: J. M. Bachar et al. (ed.s), Radical Banach Algebras and Automatic Continuity, Lectures Notes in Mathematics 975, pp. 375–396. Sprinver Verlag, 1983
Bade, W. G., Curtis, Jr. P. C., Dales, H. G.: Amenability and weak amenability for Beurling and Lipschitz algebras. Proc. London Math. Soc. 55 , 359–377 (1987)
Brown, G., Moran, W.: Point derivations on M(G). Bull. London Math. Soc. 8, 57–64 (1976)
Dales, H. G., Ghahramani, F., Helemskii, A. Ya.: The amenability of measure algebras. J. London Math. Soc. 66(2), 213–226 (2002)
Effros, E. G., Ruan, Z.-J.: Operator Spaces. Oxford University Press, 2000
Eymard, P.: L’algèbre de Fourier d’un groupe localement compact. Bull. Soc. Math. France 92 , 181–236 (1964)
Forrest, B. E.: Amenability and bounded approximate identities in ideals of A(G). Illinois J. Math. 34, 1–25 (1987)
Forrest, B. E.: Amenability and ideals in A(G). J. Austral. Math. Soc. A 53 , 143–155 (1992)
Forrest, B. E.: Fourier analysis on coset spaces. Rocky Mountain J. Math. 28, 173–190 (1998)
Forrest, B. E.: Amenability and weak amenability of the Fourier algebra. Preprint (2000)
Forrest, B. E., Wood, P. J.: Cohomology and the operator space structure of the Fourier algebra and its second dual. Indiana Univ. Math. J. 50, 1217–1240 (2001)
Forrest, B. E., Kaniuth, E., Lau, A. T.-M., Spronk, N.: Ideals with bounded approximate identities in Fourier algebras. J. Funct. Anal. 203, 286–304 (2003)
Grønbæk, N.: A characterization of weakly amenable Banach algebras. Studia Math. 94, 149–162 (1989)
Helemskii, A. Ya.: The Homology of Banach and Topological Algebras (translated from the Russian). Kluwer Academic Publishers, 1989
Hewitt, E., Ross, K. A.: Abstract Harmonic Analysis. I. Springer Verlag, 1963
Host, B.: Le théorème des idempotents dans B(G). Bull. Soc. Math. France 114, 215–223 (1986)
Ilie, M.: Homomorphisms of Fourier Algebras and Coset Spaces of a Locally Compact Group. Ph.D. thesis, University of Alberta, 2003
Ilie, M., Spronk, N.: Completely bounded homomorphisms of the Fourier algebras. J. Funct. Anal. (to appear)
Johnson, B. E.: Cohomology in Banach algebras. Mem. Amer. Math. Soc. 127, (1972)
Johnson, B. E.: Approximate diagonals and cohomology of certain annihilator Banach algebras. Amer. J. Math. 94, 685–698 (1972)
Johnson, B. E.: Non-amenability of the Fourier algebra of a compact group. J. London Math. Soc. 50(2), 361–374 (1994)
Lau, A. T.-M., Loy, R. J., Willis, G. A.: Amenability of Banach and C*-algebras on locally compact groups. Studia Math. 119, 161–178 (1996)
Leptin, H.: Sur l’algèbre de Fourier d’un groupe localement compact. C. R. Acad. Sci. Paris, Sér. A 266, 1180–1182 (1968)
Losert, V.: On tensor products of Fourier algebras. Arch. Math. (Basel) 43, 370–372 (1984)
Moore, C. C.: Groups with finite dimensional irreducible representations. Trans. Amer. Math. Soc. 166, 401–410 (1972)
Palmer, T. W.: Banach Algebras and the General Theory of *-Algebras, II. Cambridge University Press, 2001
Paterson, A. L. T.: Amenability. American Mathematical Society, 1988
Ruan, Z.-J.: The operator amenability of A(G). Amer. J. Math. 117, 1449–1474 (1995)
Rudin, W.: Fourier Analysis on Groups. Wiley-Interscience, 1990
Runde, V.: Lectures on Amenability. Lecture Notes in Mathematics 1774, Springer Verlag, 2002
Runde, V.: Operator Figà-Talamanca–Herz algebras. Studia Math. 155, 153–170 (2003)
Runde, V.: (Non-)amenability of Fourier and Fourier–Stieltjes algebras. Preprint (2002)
Runde, V., Spronk, N.: Operator amenability of Fourier-Stieltjes algebras. Math. Proc. Cambridge Phil. Soc. 136, 675–686 (2004)
Spronk, N.: Operator weak amenability of the Fourier algebra. Proc. Amer. Math. Soc. 130, 3609–3617 (2002)
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Research supported by NSERC under grant no. 90749-00.
Research supported by NSERC under grant no. 227043-00.
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Forrest, B., Runde, V. Amenability and weak amenability of the Fourier algebra. Math. Z. 250, 731–744 (2005). https://doi.org/10.1007/s00209-005-0772-2
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DOI: https://doi.org/10.1007/s00209-005-0772-2