3 research outputs found

    Hypercyclic operators and rotated orbits with polynomial phases

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    An important result of León-Saavedra and Müller says that the rotations of hypercyclic operators remain hypercyclic. We provide extensions of this result for orbits of operators which are rotated by unimodular complex numbers with polynomial phases. On the other hand, we show that this fails for unimodular complex numbers whose phases grow to infinity too quickly, say at a geometric rate. A further consequence of our work is a notable strengthening of a result due to Shkarin which concerns variants of León-Saavedra and Müller's result in a non-linear setting

    COMMON HYPERCYCLIC VECTORS FOR HIGH DIMENSIONAL FAMILIES OF OPERATORS

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    Let (Tλ)λ∈Λ(T_\lambda)_{\lambda\in\Lambda} be a family of operators acting on a FF-space XX, where the parameter space Λ\Lambda is a subset of Rd\mathbb R^d. We give sufficient conditionson the family to yield the existence of a vector x∈Xx\in X such that, for any λ∈Λ\lambda\in\Lambda, the set {Tλnx; n≥1}\big\{T_\lambda^n x;\ n\geq 1\big\} is dense in XX. We obtain results valid for any value of d≥1d\geq 1 whereas the previously known results where restricted to d=1d=1. Our methods also shed new light on the one-dimensional case

    A complex systems approach to education in Switzerland

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    The insights gained from the study of complex systems in biological, social, and engineered systems enables us not only to observe and understand, but also to actively design systems which will be capable of successfully coping with complex and dynamically changing situations. The methods and mindset required for this approach have been applied to educational systems with their diverse levels of scale and complexity. Based on the general case made by Yaneer Bar-Yam, this paper applies the complex systems approach to the educational system in Switzerland. It confirms that the complex systems approach is valid. Indeed, many recommendations made for the general case have already been implemented in the Swiss education system. To address existing problems and difficulties, further steps are recommended. This paper contributes to the further establishment complex systems approach by shedding light on an area which concerns us all, which is a frequent topic of discussion and dispute among politicians and the public, where billions of dollars have been spent without achieving the desired results, and where it is difficult to directly derive consequences from actions taken. The analysis of the education system's different levels, their complexity and scale will clarify how such a dynamic system should be approached, and how it can be guided towards the desired performance
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