RT Journal Article T1 A characterization of Gromov hyperbolicity of surfaces with variable negative curvature A1 Portilla, Ana A1 Tourís, Eva AB In this paper we show that, in order to check Gromov hyperbolicity of any surface with curvature $K \leq -k^2 < 0$, we just need to verify the Rips condition on a very small class of triangles, namely, those contained in simple closed geodesics. This result is, in fact, a new characterization of Gromov hyperbolicity for this kind of surfaces. PB Universitat Autònoma de Barcelona, Departament de Matemàtiques SN 0214-1493 YR 2009 FD 2009 LK https://hdl.handle.net/10016/6445 UL https://hdl.handle.net/10016/6445 LA eng NO 18 pages, 4 figures.-- MSC2000 codes: 53C15, 53C21, 53C22, 53C23. NO MR#: MR2474116 (2009k:53091) NO Zbl#: Zbl 1153.53320 NO Research partially supported by three grants from M.E.C. (MTM 2006-13000-C03-02, MTM 2006-11976 and MTM 2006-26627-E), and a grant from U.C.IIIM./C.A.M. (CCG07-UC3M/ESP-3339), Spain. DS e-Archivo RD 31 may. 2024