Between the late 1960s and the beginning of the 1980s, the wide recognition that simple dynamical laws could give rise to complex behaviors was sometimes hailed as a true scientific revolution impacting several disciplines, for which a striking label was coined— " chaos. " Mathematicians quickly pointed out that the purported revolution was relying on the… (More)
Brillouin zones were introduced by Brillouin [Br] in the thirties to describe quantum mechanical properties of crystals, that is, in a lattice in R n. They play an important role in solid-state physics. It was shown by Bieberbach [Bi] that Brillouin zones tile the underlying space and that each zone has the same area. We generalize the notion of Brillouin… (More)
In this note we consider the well known Hannay-Ozorio de Almeida sum formula from a mathematically rigorous viewpoint. In particular, we discuss situations where we can obtain the Sinai-Ruelle-Bowen measure as a limit taken over periodic orbits with periods in an interval which shrinks as it moves to infinity.
Galileo, in the XVII century, observed that the small oscillations of a pendulum seem to have constant period. In fact, the Taylor expansion of the period map of the pendulum is constant up to second order in the initial angular velocity around the stable equilibrium. It is well known that, for small oscillations of the pendulum and small intervals of time,… (More)
La teoría moderna de Ecuaciones en Derivadas Parciales tiende a verlas como Sistemas Dinámicos en espacios funcionales. Ello permite utilizar toda la maqui-naria del Análisis Funcional para estudiar no sólo las cuestiones de existencia y unicidad sino también las propiedades más relevantes de las soluciones. Nuestro interés en este artículo es el… (More)
The functional integrity of the sperm (SPTZ) membrane is believed to be an important factor in fertilization. This function was assessed by Jeyendran et al. (Journal of Reproduction and Fertility, 70: 219-228, 1984), who concluded that when SPTZ from normal fertile men are exposed to a hypo-osmotic solution with an ionic strength of 0.15 mol/l, 60% or more… (More)