The Teichmüller Space of a 3-Dimensional Anosov Flow
Ruihao Gu, Yi Shi
TL;DR
The paper develops a Teichmüller-type parametrization for smooth orbit-equivalence classes of 3D transitive Anosov flows on closed 3-manifolds by representing orbit data with pairs of Hölder Jacobian data $(f_s,f_u)$ modulo flow-cohomology, thereby realizing the Teichmüller space as a product of function spaces. It proves a Cawley-type realization for flows, establishes path-connectedness of the orbit-equivalence space, and derives rigidity and classification results for flows with $C^1$-smooth strong unstable foliations, including a dichotomy: either constant-roof suspensions or leafwise smoothness of the conjugacy. The key tools are Radon–Nikodym realizations of transverse measures along stable/unstable foliations, Livšic-type cohomology results for cocycles, and careful deformation of HA-flows (time-change and foliation-regularity preserving) to realize prescribed Jacobians. Together, these results provide a concrete, cohomology-based description of the moduli of 3D Anosov flows, with implications for the topology of the orbit-equivalence space and for rigidity classes under smooth foliations.
Abstract
For a $3$-dimensional transitive Anosov flow, we realize its Teichmüller space of smooth orbit-equivalence classes as a product of two Jacobian function spaces. This proves Cawley's theorem [8] for 3-dimensional transitive Anosov flows. As an application, we show the path-connectedness of orbit-equivalence class of $3$-dimensional transitive Anosov flows, which gives a positive answer of Potrie [40, Question 1] in dimension 3. Moreover, we show the stable Jacobian rigidity of time-preserving conjugacy for $3$-dimensional transitive Anosov flows admitting $C^1$-smooth strong unstable foliations.
