Browsing by Subject "Rotation number"
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On 2 and 3periodic Lyness difference equations
(20110609)
Article
Open AccessWe describe the sequences {xn}n given by the nonautonomous secondorder Lyness difference equations xnþ2 ¼ ðan þ xnþ1Þ=xn, where {an}n is either a 2periodic or a 3 periodic sequence of positive values and the initial ... 
On periodic solutions of 2periodic Lyness difference equations
(20120104)
Other
Open AccessWe study the existence of periodic solutions of the nonautonomous periodic Lyness' recurrence u_{n+2}=(a_n+u_{n+1})/u_n, where {a_n} is a cycle with positive values a,b and with positive initial conditions. It is known ... 
On Poncelet's maps
(20100808)
Article
Open AccessGiven two ellipses, one surrounding the other one, Poncelet introduced a map P from the exterior one to itself by using the tangent lines to the interior ellipse. This procedure can be extended to any two smooth, nested ... 
On two and three periodic Lyness difference equations
(20091226)
External research report
Open AccessWe describe the sequences {x_n}_n given by the nonautonomous second order Lyness difference equations x_{n+2}=(a_n+x_{n+1})/x_n, where {a_n}_n is either a 2periodic or a 3periodic sequence of positive values and the ... 
Resonance tongues and spectral gaps in quasiperiodic schrödinger operators with one or more frequencies. A numerical exploration
(201007)
External research report
Open AccessAbstract. In this paper we investigate numerically the spectrum of some representative examples of discrete onedimensional Schr¨odinger operators with quasiperiodic potential in terms of a perturbative constant b and ... 
Resonance tongues in the quasiperiodic hillSchrödinger equation with three frequencies
(201007)
External research report
Open AccessIn this paper we investigate numerically the following Hill’s equation x00 + (a + bq(t))x = 0 where q(t) = cos t + cosp2t + cosp3t is a quasiperiodic forcing with three rationally independent frequencies. It appears,also, as ...