A majorant problem.
Let f(z) and g(z) be holomorphic in the open unit disk D and let Zf and Zg be their zero sets. If Zf ⊃ Zg and |f(z)| ≥ |g(z)| (1/2 e-2 < |z| < 1), then || f || ≥ || g || where || · || is the Bergman norm: || f ||2 = π-1 ∫D |f(z)|2 dm (dm is the Lebesgue area measure).
In this paper we show that to check Gromov hyperbolicity of any surface of constant negative curvature, or Riemann surface, we only need to verify the Rips condition on a very small class of triangles, namely, those obtained by marking three points in a simple closed geodesic. This result is, in fact, a new characterization of Gromov hyperbolicity for Riemann surfaces.