So I've been skimming Bowen's 1972 paper "Symbolic Dynamics for Hyperbolic Flows" hoping it would give me some insight into how to build a Markov family for the cat flow (i.e., the Anosov flow obtained by suspension of the cat map with unit height). For the sake of completeness, the cat flow $\phi$ is obtained as follows:

i. Consider the cat map $A$ on the 2-torus and identify points $(Ax,z)$ and $(x,z+1)$ to obtain a 3-manifold $M$

ii. Equip $M$ with a suitable metric (e.g., $ds^2 = \lambda_+^{2z}dx_+^2 + \lambda_-^{2z}dx_-^2 + dz^2$, where $x_\pm$ are the expanding and contracting directions of $A$ and $\lambda_\pm$ are the corresponding eigenvalues.)

iii. Consider the flow generated by the vector field $(0,1)$ on $M$--that's the cat flow.

Unfortunately I'm getting stuck at the first part of Bowen's quasi-constructive proof, which requires finding a suitable set of disks and subsets transverse to the flow. Rather than rehash the particular criteria for a set of disks and subsets used in Bowen's construction, I will relay a simpler but very similar set of criteria, for a *proper family* (which if it meets some auxiliary criteria is also a Markov family):

$\mathcal{T} =$ {$T_1,\dots,T_n$} is called a proper family (of size $\alpha$) iff there are differentiable closed disks $D_j$ transverse to the flow s.t.

- the $T_j$ are closed
- $M = \phi_{[-\alpha, 0]}\Gamma(\mathcal{T})$, where $\Gamma(\mathcal{T}) = \cup_j T_j$
- $\dim D_j = \dim M - 1$
- diam $D_j < \alpha$
- $T_j \subset$ int $D_j$ and $T_j = \bar{T_j^*}$ where $T_j^*$ is the relative interior of $T_j$ in $D_j$
- for $j \ne k$, at least one of the sets $D_j \cap \phi_{[0,\alpha]}D_k$, $D_k \cap \phi_{[0,\alpha]}D_j$ is empty.

I've been stuck on even constructing such disks and subsets (let alone where the subsets are rectangles in the sense of hyperbolic dynamics). Bowen said this sort of thing is easy and proceeded under the assumption that the disks and subsets were already in hand. I haven't found it to be so. The thing that's killing me is 6, otherwise neighborhoods of the Adler-Weiss Markov partition for the cat map would fit the bill and the auxiliary requirements for the proper family to be a Markov family.

I've really been stuck in the mud on this one, could use a push.