Existence and uniqueness of limit cycles for generalized -Laplacian Liénard equations

Agraïments: The first author is also supported by a PNPD/CAPES grant. The third author is supported by FQM-1861 (Junta de Andalucía) grants.The Liénard equation x'' + f(x)x' + g(x) = 0 appears as a model in many problems of science and engineering. Since the first half of the 20th century, many papers have appeared providing existence and uniqueness conditions for limit cycles of Li'enard equations. In this paper we extend some of these results for the case of the generalized ϕ-Laplacian Liénard equation, (ϕ(x'))' + f(x)ψ(x') + g(x) = 0. This generalization appears when derivations of the equation different from the classical one are considered. In particular, the relativistic van der Pol equation, [x'/p1 − (x'/c)2]'+ µ(x2 − 1)x' + x = 0, has a unique periodic orbit when µ 6= 0

The Past and Future of Analytic Philosophy in Spain : XX Years of Taller d?Investigació en Filosofia

Introduction to the Special Issue for the XX Years of TIF, ed. by M. Cabrera, J. Gimeno-Simó and S. Pérez-González Introdución al Número Monográfico que conmemora los XX años del TIF, editado por M. Cabrera, J. Gimeno-Simó y S. Pérez-González Introdució al Número Monogràfic que commemora els XX anys del TIF, editat per M. Cabrera, J. Gimeno-Simó i S. Pérez-Gonzále