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Various Properties of Sturmian Words [PDF]

open access: yes, 2005
This overview paper is devoted to Sturmian words. The first part summarizes different characterizations of Sturmian words. Besides the well known theorem of Hedlund and Morse it also includes recent results on the characterization of Sturmian words using
P. Baláži, Baláži, P.
core   +1 more source

Critical Oscillation Constant for Difference Equations with Almost Periodic Coefficients

open access: yesAbstract and Applied Analysis, Volume 2012, Issue 1, 2012., 2012
We investigate a type of the Sturm‐Liouville difference equations with almost periodic coefficients. We prove that there exists a constant, which is the borderline between the oscillation and the nonoscillation of these equations. We compute this oscillation constant explicitly.
Petr Hasil   +2 more
wiley   +1 more source

On Constants in Nonoscillation Criteria for Half‐Linear Differential Equations

open access: yesAbstract and Applied Analysis, Volume 2011, Issue 1, 2011., 2011
We study the half‐linear differential equation (r(t)Φ(x′)) ′ + c(t)Φ(x) = 0, where Φ(x) = |x|p−2x, p > 1. Using the modified Riccati technique, we derive new nonoscillation criteria for this equation. The results are closely related to the classical Hille‐Nehari criteria and allow to replace the fixed constants in known nonoscillation criteria by a ...
Simona Fišnarová   +2 more
wiley   +1 more source

Weyl‐Titchmarsh Theory for Time Scale Symplectic Systems on Half Line

open access: yesAbstract and Applied Analysis, Volume 2011, Issue 1, 2011., 2011
We develop the Weyl‐Titchmarsh theory for time scale symplectic systems. We introduce the M(λ)‐function, study its properties, construct the corresponding Weyl disk and Weyl circle, and establish their geometric structure including the formulas for their center and matrix radii. Similar properties are then derived for the limiting Weyl disk. We discuss
Roman Šimon Hilscher   +2 more
wiley   +1 more source

The distribution of nonprincipal eigenvalues of singular second‐order linear ordinary differential equations

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2006, Issue 1, 2006., 2006
We obtain the asymptotic distribution of the nonprincipal eigenvalues associated with the singular problem x″ + λq(t)x = 0 on an infinite interval [a, +∞). Similar to the regular eigenvalue problem on compact intervals, we can prove a Weyl‐type expansion of the eigenvalue counting function, and we derive the asymptotic behavior of the eigenvalues.
Juan Pablo Pinasco
wiley   +1 more source

Symplectic difference systems: oscillation theory and hyperbolic Prüfer transformation

open access: yesAbstract and Applied Analysis, Volume 2004, Issue 4, Page 285-294, 2004., 2004
We present basic methods of oscillation theory of symplectic difference systems (SDSs). A particular attention is devoted to the variational principle and to the transformation method. Hyperbolic Prüfer transformation for SDSs is established.
Ondřej Došlý
wiley   +1 more source

On certain comparison theorems for half‐linear dynamic equations on time scales

open access: yesAbstract and Applied Analysis, Volume 2004, Issue 7, Page 551-565, 2004., 2004
We obtain comparison theorems for the second‐order half‐linear dynamic equation [r(t)Φ(yΔ)]Δ+p(t)Φ(yσ)=0, where Φ(x) = |x|α−1sgn x with α > 1. In particular, it is shown that the nonoscillation of the previous dynamic equation is preserved if we multiply the coefficient p(t) by a suitable function q(t) and lower the exponent α in the nonlinearity Φ ...
Pavel Řehák
wiley   +1 more source

Substitutions and their Generalisations

open access: yesIsrael Journal of Chemistry, Volume 64, Issue 10-11, November 2024.
Abstract Tilings and point sets arising from substitutions are classical mathematical models of quasicrystals. Their hierarchical structure allows one to obtain concrete answers regarding spectral questions tied to the underlying measures and potentials.
Neil Mañibo
wiley   +1 more source

On polynomials of Sheffer type arising from a Cauchy problem

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 33, Page 2119-2137, 2003., 2003
A new sequence of eigenfunctions is developed and studied in depth. These theta polynomials are derived from a recent analytic solution of the canonical Cauchy problem for parabolic equations, namely, the inverse heat conduction problem. By appealing to the methods of the operator calculus, it is possible to categorize the new functions as polynomials ...
D. G. Meredith
wiley   +1 more source

Sturmian theorems for systems of differential equations

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 3, Issue 1, Page 177-184, 1980., 1979
Two Sturmian theorems are established for second order linear nonhomogeneous systems of two differential equations with the use of a maximum principle. The results also hold for homogeneous systems. For illustration, an example is given.
C. Y. Chan
wiley   +1 more source

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