Central Sets Theorem on noncommutative semigroups

• Published in: Indagationes mathematicae Vol. 30; no. 2; pp. 329 - 339
• Main Authors: Keshavarzian, J., Tootkaboni, M.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2019; Elsevier Science Ltd
• Subjects: [formula omitted]-set; Central Sets Theorem; Piecewise syndetic set; Stone–[formula omitted]ech compactification; Theorems; Central Sets Theorem; Stone–Cˇech compactification; Piecewise syndetic set; C-set; J-set

Let D be a directed set without maximal element, S be an infinite semigroup and DS be the collection of all functions from D into S. It is shown that for a commutative semigroup S, A⊆S is a C-set with respect to NS if and only if A is a C-set with respect to DS. We investigate the Central Sets Theor...