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3F-products and nonstandard hulls for semigroupsMathematical Logic Quarterly 50 (1): 18. 2004.Derndinger [2] and Krupa [5] defined the F-product of a semigroup and presented some applications . Wolff investigated some kind of nonstandard analogon and applied it to spectral theory of group representations. The question arises in which way these constructions are related. In this paper we show that the classical and the nonstandard F-product are isomorphic . We also prove a little “classical” corollary
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1 Kurt Gödel Research Center for Mathematical Logic, Universität Wien, Währinger Strasse 25, 1090 Wien 2 Einstein Institute of Mathematics, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, 91904 3 Department of Mathematics, Rutgers University, New Brunswick, NJ 08854 (review)Journal of Symbolic Logic 76 (4): 1153-1183. 2011.