$\varphi$-Connes amenability of dual Banach algebras

Document Type : Research Paper

Authors

1 Department of‎ ‎Mathematics‎, ‎Semnan University‎, ‎P.O‎. ‎Box 35195-363‎, ‎Semnan‎, ‎Iran.

2 Department of‎ ‎Mathematics, ‎Semnan University, ‎P.O‎. ‎Box 35195-363‎, ‎Semnan‎, ‎Iran.

Abstract

‎Generalizing the notion of character amenability for Banach‎ ‎algebras‎, ‎we study the concept of $\varphi$-Connes amenability of‎ ‎a dual Banach algebra $\mathcal{A}$ with predual $\mathcal{A}_*$‎, ‎where $\varphi$ is a homomorphism from $\mathcal{A}$ onto $\Bbb C$‎ ‎that lies in $\mathcal{A}_*$‎. ‎Several characterizations of‎ ‎$\varphi$-Connes amenability are given‎. ‎We also prove that the‎ ‎following are equivalent for a unital weakly cancellative‎ ‎semigroup algebra $l^1(S)$‎:
(i) $S$ is $\chi$-amenable‎.
(ii) $l^1(S)$ is $\hat{\chi}$-Connes amenable‎.
(iii) $l^1(S)$ has a $\hat{\chi}$-normal‎, ‎virtual diagonal‎.

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Main Subjects


H. P. Aghababa, L. Y. Shi and Y. J. Wu, Generalized notions of character amenability, Acta Math. Sin. 29 (2013), no. 7, 1329--1350.
F. F. Bonsall and J. Duncan, Complete Normed Algebras, Springer-Verlag, Berlin, 1973.
G. Corach and J. E. Gale, Averaging with virtual diagonals and geometry of representations, in: E. Albrecht and M. Mathieu (eds.), Banach Algebras, 97, Walter de Grutyer, Berlin, 1998.
H. G. Dales, Banach Algebras and Automatic Continuity, London Math. Soc. Monogr. ser. Clarendon Press, 2000.
H. G. Dales, A. T. Lau, and D. Strauss, Banach algebras on semigroups and their compactifications, Mem. Amer. Math. Soc. 205 (2010), no. 966, 165 pages.
M. Daws, Connes amenability of bidual and weighted semigroup algebras, Math. Scand. 99 (2006), no. 2, 217--246.
A. Defant and K. Floret, Tensor Norms and Operator Ideals, North-Holland, 1993. [8] E. G. Effros, Amenability and virtual diagonals for von Neumann algebras, J. Funct. Anal. 78 (1988), no. 1, 137--153.
G. H. Esslamzadeh, B. Shojaee and A. Mahmoodi, Approximate Connes-amenability of dual Banach algebras, Bull. Belg. Math. Soc. Simon Stevin 19 (2012), no. 2, 193--213.
A. Ghaffari, On character amenability of semigroup algebras, Acta Math. Hungar. 134 (2012), no. 1-2, 177--192.
F. Ghahramani, R. J. Loy and G. A. Willis, Amenability and weak amenability of second conjugate Banach algebras, Proc. Amer. Math. Soc. 124 (1996), no. 5, 1489--1497.
A. Ya. Helemskii, Homological essence of amenability in the sense of A. Connes: the injectivity of the predual bimodule, Sb. Math. 68 (1991) 555--566.
Z. Hu, M. S. Monfared and T. Traynor, On character amenable Banach algebras, Studia Math. 193 (2009) 53--78.
B. E. Johnson, Cohomology in Banach Algebras, Mem. Amer. Math. Soc. 127, Amer. Math. Soc. Providence RI, 1972.
B. E. Johnson, R. V. Kadison and J. Ringrose, Cohomology of operator algebras III, Bull. Soc. Math. France 100 (1972) 73--79.
E. Kaniuth, A. T. Lau and J. Pym, On φ-amenability of Banach algebras, Math. Proc. Cambridge Philos. Soc. 144 (2008), no. 1, 85--96.
E. Kaniuth, A. T. Lau and J. Pym, On character amenability of Banach algebras, J. Math. Anal. Appl. 344 (2008), no. 2, 942--955.
M. S. Monfared, Character amenability of Banach algebras, Math. Proc. Cambridge Philos. Soc. 144 (2008), no. 3, 697--706.
W. Rudin, Functional Analysis, McGraw Hill, New York, 1991.
V. Runde, Lectures on Amenability, Lecture Notes in Math., 1774, Springer Verlag, Berlin, 2002.
V. Runde, Amenability for dual Banach algebras, Studia Math. 148 (2001), no. 1, 47--66.
V. Runde, Connes amenability and normal virtual diagonals for measure algebras I, J. Lond. Math. Soc. 67 (2003), no. 3, 643--656.
V. Runde, Connes amenability and normal virtual diagonals for measure algebras II, Bull. Aust. Math. Soc. 68 (2003), no. 2, 325--328.
V. Runde, Dual Banach algebras: Connes amenability, normal, virtual diagonals, and injectivity of the predual bimodule, Math. Scand. 95 (2004), no. 1, 124--144.