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Fair amenability for semigroups. (English) Zbl 1338.43001

Summary: A new flavour of amenability for discrete semigroups is proposed that generalises group amenability and follows from a Følner-type condition. Some examples are explored, to argue that this new notion better captures some essential ideas of amenability. A semigroup \(S\) is left fairly amenable if, and only if, it supports a mean \(m \in \ell^\infty(S)^\ast\) satisfying \(m(f) = m(s \ast f)\) whenever \(s \ast f \in \ell^\infty(S)\), thus justifying the nomenclature “fairly amenable”.

MSC:

43A07 Means on groups, semigroups, etc.; amenable groups

Online Encyclopedia of Integer Sequences:

House numbers: a(n) = (n+1)^3 + Sum_{i=1..n} i^2.

References:

[1] Argabright, L. N.; Wilde, C. O., Semigroups satisfying a strong Følner condition, Proc. Amer. Math. Soc., 18, 4, 587-591 (1967) · Zbl 0152.33302
[2] Bergelson, V., Multiplicatively large sets and ergodic Ramsey theory, Israel J. Math., 148, 1, 23-40 (2005) · Zbl 1093.11003
[3] Clifford, A. H.; Preston, G. B., The Algebraic Theory of Semigroups, American Mathematical Society Mathematical Surveys, vol. 2 (1967), American Mathematical Society · Zbl 0178.01203
[4] Day, M. M., Amenable semigroups, Illinois J. Math. (1957) · Zbl 0078.29402
[5] Donnelly, J., Subsemigroups of cancellative amenable semigroups, Int. J. Contemp. Math. Sci., 7, 23, 1131-1137 (2012) · Zbl 1254.43002
[6] Duncan, J.; Namioka, I., Amenability of inverse semigroups and their semigroup algebras, Proc. Roy. Soc. Edinburgh Sect. A, 80, 309-321 (1978) · Zbl 0393.22004
[7] Følner, E., On groups with full Banach mean value, Math. Scand., 3, 243-254 (1955) · Zbl 0067.01203
[8] Howie, J. M., An Introduction to Semigroup Theory, L.M.S. Monographs (1976), Academic Press · Zbl 0355.20056
[9] Johnson, B. E., Approximate diagonals and cohomology of certain annihilator Banach algebras, Amer. J. Math., 94, 3, 685-698 (1972) · Zbl 0246.46040
[10] Jones, D. G.; Lawson, M. V., Graph inverse semigroups: their characterization and completion (2011)
[11] Lawson, M. V., Inverse Semigroups (1998), World Scientific Publishing Co. P/L · Zbl 1079.20505
[12] Lawson, M. V., Representations of the Thompson group F via representations of the polycyclic monoid on two generators (2004)
[13] Milan, D., C*-algebras of inverse semigroups: amenability and weak containment (2007)
[14] Milan, D., C*-algebras of inverse semigroups (2008), University of Nebraska, PhD thesis
[15] Namioka, I., Følner’s conditions for amenable semi-groups, Math. Scand., 15, 18-28 (1964) · Zbl 0138.38001
[16] On-line encyclopedia of integer sequences, A051662 (2013)
[17] Paterson, A. L.T., Amenability (1988), American Mathematical Society · Zbl 0648.43001
[18] Paterson, A. L.T., Groupoids, Inverse Semigroups, and Their Operator Algebras (1998), Birkhäuser: Birkhäuser Boston
[19] Runde, V., Lectures on Amenability, Lecture Notes in Mathematics (2002), Springer Verlag · Zbl 0999.46022
[20] van Douwen, E. K., Finitely additive measures on \(N\), Topology Appl., 47, 3, 223-268 (1992) · Zbl 0762.28010
[21] von Neumann, J., Zur allgemeinen Theorie des Masses, Fund. Math., 13, 73-116 (1929) · JFM 55.0151.01
[22] Wagon, S., The Banach-Tarski Paradox (1993), Cambridge University Press · Zbl 0569.43001
[23] Yang, Z., Følner numbers and Følner type conditions for amenable semigroups, Illinois J. Math., 31, 3, 496-517 (1987) · Zbl 0612.43001
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