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Hyperbolicity on Riemann Surfaces

For Riemann surfaces there are at least to possible notions of hyperbolicity. The classical one given by the Uniformization Theorem, or equivalently the type problem, which essentially says that a simply connected Riemann surfaces is conformally equivalent to one of the following:

  • Riemann Sphere $\mathbb{C}\cup\{\infty\}$ (elliptic type).
  • Complex plane (parabolic type).
  • Open unit disk (hyperbolic type).

On the other hand, given a Riemann surface one can asks if it is hyperbolic in the Gromov's sense. In other words, does there exists $\delta>0$ such that all the geodesic triangles in the surface are $\delta$-thin?

It seems to me that this two notions of hyperbolicity are not equivalent and one can have counterexamples in both directions. For instance, the two dimensional torus $\mathbb{T}^2$ is hyperbolic in Gromov's sense (since it is compact) but it is conformally equivalent to the complex plane and therefore of parabolic type.

My questions is: what is necessary to guarantee that a surface of hyperbolic type is also Gromov's hyperbolic? what is known about the relation of these two notions?

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