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We investigate the set of invariant idempotent probabilities for countable idempotent iterated function systems (IFS) defined in compact metric spaces. We demonstrate that, with constant weights, there exists a unique invariant idempotent…

Dynamical Systems · Mathematics 2024-07-09 Elismar R. Oliveira

There is a class of physical filtration processes where the input is adequately modeled by a continuous periodic function f (x) of bounded variation over its period, and the output depends only on certain harmonics of the Fourier expansion…

General Mathematics · Mathematics 2024-12-17 Vladimir Sluchak

Following the work of Louisa and Michael Barnsley on results in tops of iterated function systems, we extend their work to graph-directed iterated function systems by investigating the relationship between top addresses and shift spaces.…

Dynamical Systems · Mathematics 2024-02-05 Grover Lancaster-Cole , Georgiana Lyall , Thomas Malcolm , Qiyu Zhou

Shape-invariant signals under Fourier transform are investigated leading to a class of eigenfunctions for the Fourier operator. The classical uncertainty Gabor-Heisenberg principle is revisited and the concept of isoresolution in joint…

Classical Analysis and ODEs · Mathematics 2015-02-18 L. R. Soares , H. M. de Oliveira , R. J. Cintra , R. M. Campello de Souza

For multi-variable finite measure spaces, we present in this paper a new framework for non-orthogonal $L^2$ Fourier expansions. Our results hold for probability measures $\mu$ with finite support in $\mathbb{R}^d$ that satisfy a certain…

Functional Analysis · Mathematics 2024-02-27 Chad Berner , John E. Herr , Palle E. T. Jorgensen , Eric S. Weber

In this work we present iterated function systems with general measures(IFSm) formed by a set of maps $\tau_{\lambda}$ acting over a compact space $X$, for a compact space of indices, $\Lambda$. The Markov process $Z_k$ associated to the…

Dynamical Systems · Mathematics 2025-05-15 Elismar R. Oliveira , Rafael R. Souza

We consider iterated functions systems (IFS) on compact metric spaces and introduce the concept of target sets. Such sets have very rich dynamical properties and play a similar role as semifractals introduced by Lasota and Myjak do for…

Dynamical Systems · Mathematics 2018-08-31 Lorenzo J. Díaz , Edgar Matias

We here revisit Fourier analysis on the Heisenberg group H^d. Whereas, according to the standard definition, the Fourier transform of an integrable function f on H^d is a one parameter family of bounded operators on L 2 (R^d), we define (by…

Classical Analysis and ODEs · Mathematics 2016-09-14 Hajer Bahouri , Jean-Yves Chemin , Raphael Danchin

Let $(b_k)_{k = 0}^\infty$ be strictly decreasing sequence of real numbers such that $b_0 = 1$ and $\{f_k:[b_k,b_{k-1}]\to [0,1]\}_{k\in\N}$ be decreasing functions such that $f_k(b_k) = 1$ and $f_k(b_{k-1}) = 0$, $k = 1, 2, \dots$. By…

Dynamical Systems · Mathematics 2026-03-30 Rafał Tryniecki

We study a class of functional problems reducible to computing $f^{(n)}(x)$ for inputs $n$ and $x$, where $f$ is a polynomial-time bijection. As we prove, the definition is robust against variations in the type of reduction used in its…

Computational Complexity · Computer Science 2024-02-14 David Eppstein

We present a general setting where wavelet filters and multiresolution decompositions can be defined, beyond the classical $\mathbf L^2(\mathbb R,dx)$ setting. This is done in a framework of {\em iterated function system} (IFS) measures;…

Functional Analysis · Mathematics 2022-08-31 Daniel Alpay , Palle Jorgensen , Izchak Lewkowicz

For bilinear Fourier multipliers that contain some oscillatory factors, boundedness of the operators between Lebesgue spaces is given including endpoint cases. Sharpness of the result is also considered.

Classical Analysis and ODEs · Mathematics 2024-04-17 Tomoya Kato , Akihiko Miyachi , Naoto Shida , Naohito Tomita

We investigate iterated function systems (IFS) that randomly alternate between two non-identical one-dimensional maps. Our primary focus is on finite invariant sets exhibiting ``toss-and-catch'' dynamics, in which trajectories alternate…

Dynamical Systems · Mathematics 2026-04-16 Hibiki Kato , Tamotsu Onozaki , Yoshitaka Saiki , Yasumasa Sugita

This work deals with the measurability of Fourier integral operators (FIOs) with random phase and amplitude functions. The key ingredient is the proof that FIOs depend continuously on their phase and amplitude functions, taken from suitable…

Analysis of PDEs · Mathematics 2022-08-15 Michael Oberguggenberger , Martin Schwarz

Spectral bias, the tendency of neural networks to learn low-frequency features first, is a well-known issue with many training algorithms for physics-informed neural networks (PINNs). To overcome this issue, we propose IFeF-PINN, an…

Machine Learning · Computer Science 2025-10-23 Yulun Wu , Miguel Aguiar , Karl H. Johansson , Matthieu Barreau

In this work we propose a definition of an Euroattractor: an attracting invariant measure of a certain iterated functions system (IFS). An IFS is defined by specifying a set of functions, defined in subsets of R^N or in a classical phase…

Chaotic Dynamics · Physics 2007-05-23 Karol Zyczkowski , Artur Lozinski

The possibilities for limit functions on a Fatou component for the iteration of a single polynomial or rational function are well understood and quite restricted. In non-autonomous iteration, where one considers compositions of arbitrary…

Dynamical Systems · Mathematics 2025-02-12 Mark Comerford , Christopher Staniszewski

The paper discusses the relationships between electrical and affine differential geometry quantities, establishing a link between frequency and time derivatives of voltage, through the utilization of affine geometric invariants. Based on…

Differential Geometry · Mathematics 2024-09-26 Ali Alshawabkeh , Georgios Tzounas , Angel Molina-Garcia , Federico Milano

We consider B\'ezier curves with complex parameters, and we determine explicitly the affine iterated function system (IFS) corresponding to the de Casteljau subdivision algorithm, together with the complex parametric domain over which such…

Numerical Analysis · Mathematics 2025-05-08 Lenka Ptackova , Franco Vivaldi

Functions that are smooth but non-periodic on a certain interval possess Fourier series that lack uniform convergence and suffer from the Gibbs phenomenon. However, they can be represented accurately by a Fourier series that is periodic on…

Numerical Analysis · Mathematics 2015-03-19 Ben Adcock , Daan Huybrechs
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