New York Journal of Mathematics
Volume 1 (1994-1995) 111-119


Neil Hindman and Dona Strauss

Topological and Algebraic Copies of N* in N*

Published: May 1, 1995
Keywords: Stone-Cech compactification, right topological semigroup, homomorphisms
Subject: 22A, 54D

We show that the only topological and algebraic copies of N* to be found in N* are the trivial ones, namely k⋅N* for k∈ N. A similar statement holds for copies of Z* in Z*. As a consequence, we obtain the corollary that N* contains no copies of Z* whatever.


The first author gratefully acknowledges support received from the National Science Foundation via grants DMS 9025025 and DMS 9424421.

Both authors gratefully acknowledge support received from EPSRC for the visit during which this research was conducted.

Author information

Neil Hindman:
Department of Mathematics, Howard University, Washington, DC 20059

Dona Strauss:
Department of Pure Mathematics, University of Hull, Hull HU6 7RX, UK