Trong [1] các tác giả xem xét các điều kiện ω ω đủ (n) (-n) = o (n) amenability yếu Beurling đại số trên các số nguyên. Trong bài báo này, chúng tôi cho thấy đặc tính này không khái quát được các nhóm abelian không. | Vietnam Journal of Mathematics 33 V Í e It ini ai m J o mt r im ai I of MATHEMATICS VAST 2005 Some Remarks on Weak Amenability of Weighted Group Algebras A. Pourabbas and M. R. Yegan Faculty of Mathematics and Computer Science Amirkabir University of Technology 424 Hafez Avenue Tehran Iran Abstract. 1. Introduction . . - X . . . . A . . . . . 1. . . . . . . . . . . . . . . . . 1 . 1. . . . . . . . 1 . . -1 . Z .1. . . .1. . . . . A. Pourabbas and M. R. Yegan 1. Z C .1. Theorem a weighted non-abelian group algebra and let . . . be the partition of into conjugacy classes. For each let . denote the set of nonzero functions C which are supported on . and such that . Then weakly amenable if and only if for each every element of . is contained in -1 that is if and only if every . satisfies .-1 -------- j . - .- Proposition . Let be a discrete abelian group and let be a weight on such that -y- - . for every . Then weakly amenable. Proof. 1 e yyg-y C . - - . her. . w Example . 1 -2 . . l 2 R Some Remarks on Weak Amenability . R 1 . -2 . . 1 2 . . . . 1 1 . 1 1 2 s 1 -2- 1 - . 1 1 . .2 . 1 . .2 . 1 . is 2 2 . 1. 1 . .2 - a . 2 . . - 1 . 2. - 1 1 . .- I . 2. 1 1 . 2 1 .2 1 1 a 2 . 1 1 2E R . 1 2eR 2 .a 2 . 1 1 .2- 2 2 1 .a T e 1 .a. Question . . ---------------- . . . . 1 . . 2. Main Results Example .
