Preprint D128/2016
F-expansivity for Borel measures
helmuth villavicencio fernandez
Keywords: Expansive measure | Expansive flow | Support of a measure | Metric space

We introduce the notion of F-expansive measure by making the dynamical ball in \cite{C} to depend on a given subset F of the set of all the reparametrizations H. We prove that these measures satisfy some interesting properties resembling the expansive ones. These include the equivalence with expansivity when F=H, the vanishing along the orbits, the absence of singularities in the support, the F-expansivity with respect to time t-maps, the invariance under equivalence and the characterization for suspensions. We also analyze the support of the F-expansive measures and prove that there exists a dense subset of measures (in the set of F-expansive measures) all of them with a common support. Finally, we extend to flows the recent result for homeomorphisms in \cite{A}.