“…The corresponding equations are non-linear second-order ordinary differential equations, used by physicists and mathematicians since their discovery to describe a growing variety of systems. Some examples involve the description of the asymptotic behavior of non-linear equations [2], statistical mechanics [3], correlation functions of the XY model [4], bidimensional ising model [5], superconductivity [6], Bose-Einstein condensation [6], stimulated Raman dispersion [7], quantum gravity and quantum field theory [8], aleatory matrix models [9], topologic field theory (e.g., the so-called WittenDijkgraaf-Verlinde-Verlinde equations) [10], general relativity [11], solutions of Einstein axialsymmetric equations [11], negative curvature surfaces [12], plasma physics [6], Hele-Shaw problems [13] and non-linear optics [14]. During the last years, more and more researchers are interested in these equations and they have found interesting analytic, geometric, and algebraic properties.…”