A theorem on normal semigroups
Štefan Schwarz · Czechoslovak Mathematical Journal · 1960
This paper contains a proof of a theorem concerning compact semi groups S, the idempotents of which are contained in the centre of S.Let S be a Hausdorff compact semigroup.If a is an element e 8 we shall denote by Г (a) -Г г (а) the closure of the set {a, a 2 , a 3 , ...}, and by Г п (а),.n I> 2, the closure of {a n , a n+1 , a n+2 , ...}.It is known that Г (a) contains a,