6 citations · 12 across the 6 of their papers we have counts for
6 papers
On Opial-type inequalities via fractional calculus
Ana Portilla, José M. Rodríguez, José M. Sigarreta
Inequalities play an important role in pure and applied mathematics. In particular, Opial inequality plays a main role in the study of the existence and uniqueness of initial and b…
Relations between some topological indices and the line graph
Walter Carballosa, Ana Granados, Domingo Pestana +2
The concepts of geometric-arithmetic and harmonic indices were introduced in the area of chemical graph theory recently. They have proven to correlate well with physical and chemic…
The topology of balls and Gromov hyperbolicity of Riemann surfaces
Jesús Gonzalo Pérez, Ana Portilla, José M Rodríguez +1
For each k > 0 we find an explicit function f_k such that the topology of S inside the ball B(p,r) is `bounded' by f_k(r) for every complete Riemannian surface (compact or noncompa…
Gromov hyperbolicity of Denjoy domains with hyperbolic and quasihyperbolic metrics
Peter Hästö, Henri Linden, Ana Portilla +2
We obtain explicit and simple conditions which in many cases allow one decide, whether or not a Denjoy domain endowed with the Poincare or quasihyperbolic metric is Gromov hyperbol…
A real variable characterization of Gromov hyperbolicity of flute surfaces
Ana Portilla, Jose M. Rodriguez, Eva Touris
In this paper we give a characterization of the Gromov hyperbolicity of trains (a large class of Denjoy domains which contains the flute surfaces) in terms of the behavior of a rea…
Structure Theorem for Riemannian surfaces with arbitrary curvature
Ana Portilla, Jose M. Rodriguez, Eva Touris
In this paper we prove that any Riemannian surface, with no restriction of curvature at all, can be decomposed into blocks belonging just to some of these types: generalized Y-piec…