All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 15 Next

Displaying 281 – 300 of 386

Showing per page

Tilings associated with non-Pisot matrices

Maki Furukado, Shunji Ito, E. Arthur Robinson (2006)

Annales de l’institut Fourier

Suppose A ∈ G l d ( ℤ ) has a 2-dimensional expanding subspace E u , satisfies a regularity condition, called “good star”, and has A * ≥ 0 , where A * is an oriented compound of A . A morphism θ of the free group on { 1 , 2 , ⋯ , d } is called a non-abelianization of A if it has structure matrix A . We show that there is a tiling substitution Θ whose “boundary substitution” θ = ∂ Θ is a non-abelianization of A . Such a tiling substitution Θ leads to a self-affine tiling of E u ∼ ℝ 2 with A u : = A | E u ∈ G L 2 ( ℝ ) as its expansion. In the last section we find conditions on A so...

Time series models for Earth's crust kinematics

Magda Komorníková, Jozef Komorník (2002)

Kybernetika

Deterministic and stochastic approach to modeling common trends has been applied to time series of horizontal coordinates of the permanent GPS station Modra – Piesky (recorded weekly during the period of 4 years).

Time to the convergence of evolution in the space of population states

Iwona Karcz-Dulęba (2004)

International Journal of Applied Mathematics and Computer Science

Phenotypic evolution of two-element populations with proportional selection and normally distributed mutation is considered. Trajectories of the expected location of the population in the space of population states are investigated. The expected location of the population generates a discrete dynamical system. The study of its fixed points, their stability and time to convergence is presented. Fixed points are located in the vicinity of optima and saddles. For large values of the standard deviation...

Time weighted entropies

Jörg Schmeling (2000)

Colloquium Mathematicae

For invertible transformations we introduce various notions of topological entropy. For compact invariant sets these notions are all the same and equal the usual topological entropy. We show that for non-invariant sets these notions are different. They can be used to detect the direction in time in which the system evolves to highest complexity.

Topics on Meixner families

Marek Bożejko, Nizar Demni (2010)

Banach Center Publications

We shed some light on the inter-connections between different characterizations leading to the classical Meixner family. This allows us to give free analogs of both Sheffer's and Al-Salam and Chihara's characterizations in the classical case by the use of the free derivative operator. The paper closes with a discussion of the q-deformed case, |q| < 1.

Topological conjugacy of cascades generated by gradient flows on the two-dimensional sphere

Andrzej Bielecki (2000)

Annales Polonici Mathematici

This article presents a theorem about the topological conjugacy of a gradient dynamical system with a constant time step and the cascade generated by its Euler method. It is shown that on the two-dimensional sphere S² the gradient dynamical flow is, under some natural assumptions, correctly reproduced by the Euler method for a sufficiently small time step. This means that the time-map of the induced dynamical system is globally topologically conjugate to the discrete dynamical system obtained via...

Topological conjugation classes of tightly transitive subgroups of Homeo₊(ℝ)

Enhui Shi, Lizhen Zhou (2016)

Colloquium Mathematicae

Let ℝ be the real line and let Homeo₊(ℝ) be the orientation preserving homeomorphism group of ℝ. Then a subgroup G of Homeo₊(ℝ) is called tightly transitive if there is some point x ∈ X such that the orbit Gx is dense in X and no subgroups H of G with |G:H| = ∞ have this property. In this paper, for each integer n > 1, we determine all the topological conjugation classes of tightly transitive subgroups G of Homeo₊(ℝ) which are isomorphic to ℤⁿ and have countably many nontransitive points.

Topological dynamics of unordered Ramsey structures

Moritz Müller, András Pongrácz (2015)

Fundamenta Mathematicae

We investigate the connections between Ramsey properties of Fraïssé classes and the universal minimal flow M ( G ) of the automorphism group G of their Fraïssé limits. As an extension of a result of Kechris, Pestov and Todorcevic (2005) we show that if the class has finite Ramsey degree for embeddings, then this degree equals the size of M ( G ) . We give a partial answer to a question of Angel, Kechris and Lyons (2014) showing that if is a relational Ramsey class and G is amenable, then M ( G ) admits a unique invariant...

Topological entropy and differential equations

Ján Andres, Pavel Ludvík (2023)

Archivum Mathematicum

On the background of a brief survey panorama of results on the topic in the title, one new theorem is presented concerning a positive topological entropy (i.e. topological chaos) for the impulsive differential equations on the Cartesian product of compact intervals, which is positively invariant under the composition of the associated Poincaré translation operator with a multivalued upper semicontinuous impulsive mapping.

Currently displaying 281 – 300 of 386