MODELING EXPANSION IN REAL FLOWS

We show that any real flow without fixed points is the homomorphic image of a suspension of the shift on a bisequence space and the homomorphism is one-to-one between invariant residual sets. If the original flow is onedimensional this homomorphism is an isomorphism. We then use this model of a real flow to lift .f-expansiveness for any class f of continuous functions from the reals into the reals fixing zero, and thus generalize the results of Bowen and Walters [2]. Various other properties of the suspension model are discussed. © 1979, University of California, Berkeley. All Rights Reserved.