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On left thickness of subsets in semigroups


Author: James C. S. Wong
Journal: Proc. Amer. Math. Soc. 84 (1982), 403-407
MSC: Primary 43A07; Secondary 22A20
DOI: https://doi.org/10.1090/S0002-9939-1982-0640241-0
MathSciNet review: 640241
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Abstract: We reformulate the concept of left thickness in a semigroup introduced by H. Junghenn in Amenability of function spaces on thick subsemigroups, Proc. Amer. Math. Soc. 75 (1979), 37-41, and obtain a number of interesting new characterisations of left thickness without assuming left amenability. Moreover, these characterisations are similar in nature to familiar characterisations of left amenability on semigroups. We also sharpen some of Junghenn's results, paving the way for extension to locally compact semigroups.


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Additional Information

DOI: https://doi.org/10.1090/S0002-9939-1982-0640241-0
Keywords: Semigroups, left thick subsets, means, bounded functions on semigroups
Article copyright: © Copyright 1982 American Mathematical Society

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