A characterization of the standard Reeb flow (Q1946864)

This article is devoted to a characterization of the conjugation class of the Reeb flow among all possible flows topologically equivalent to it. The Reeb flow is example of a planar flow without equilibria, not conjugated to a translation. A flow, topologically conjugated to it can be made by: take two translations in opposite directions, along two disjoint and parallel half-planes; on the middle strip, any flow topologically conjugated to that given by the equations \(x '= x\), \(y' = -y\) considered in \([0, \infty) ^ 2 - \{(0,0)\}\). Two flows are topologically equivalent if there is a homeomorphism taking orbits in orbits, keeping the orientation but not necessarily the temporal evolution. The author shows that a flow topologically equivalent to the Reeb flow, is also topologically conjugated to it, if and only if \(\phi^t\) and \(\phi^{\lambda t}\) are topologically conjugated for any positive \(\lambda\). The author also shows an example in which this this condition is fulfilled for a single value of \(\lambda\) and the flow is not topologically conjugated to the Reeb flow. The proofs uses a characterization of the topological conjugation class of flows that are topologically equivalent to Reeb flow, given by \textit{F. Le Roux} [C. R. Acad. Sci., Paris, Sér. I, Math. 328, No. 1, 45--50 (1999; Zbl 0922.58069)].