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            Neil Hindman and Dona Strauss 
            Topological and Algebraic Copies of N* in N* 
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                | Published: | 
                May 1, 1995 | 
               
              
                | Keywords: | 
                Stone-Cech compactification, right topological semigroup, homomorphisms | 
               
              
                | Subject: | 
                22A, 54D | 
               
              
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			  Abstract
			  
			     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.
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			  | Acknowledgements
 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.  |  
			
			  
			      
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			  | Author information
 Neil Hindman: 
Department of Mathematics, Howard University, Washington, DC 20059
 
nhindman@howard.edu 
http://members.aol.com/nhindman/ 
 Dona Strauss: 
Department of Pure Mathematics, University of Hull, Hull HU6 7RX, UK
 
d.strauss@hull.ac.uk 
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