2011/12/24 by Taras Banakh, Igor Guran · 1 citation
Mathematics · #math.GN #math.GR #msc:20B35 #msc:20M20 #msc:22A05 #msc:22A15 #msc:54D45
paper · pdf · doi:10.2478/taa-2013-0001
published as Topological Algebra and Applications, 1 (2013) 1-8 · 6 pages
arxiv created 2011/12/24 · arxiv updated 2014/12/04
In this paper we introduce perfectly supportable semigroups and prove that they are σ-discrete in each Hausdorff shift-invariant topology. The class of perfectly supportable semigroups includes each subsemigroup S of the semigroup FRel(X) of finitely supported relations on an infinite set X such that S contains the group FSym(X) of finitely supported permutations of X.