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We generalize Dirichlet's diophantine approximation theorem to approximating any real number $\alpha$ by a sum of two rational numbers $\frac{a_1}{q_1} + \frac{a_2}{q_2}$ with denominators $1 \leq q_1, q_2 \leq N$. This turns out to be…

Number Theory · Mathematics 2007-05-23 Tsz Ho Chan

We introduce functions for relative maximization in a general context: the beta and alpha applications. After a systematic study concerning regularities, we investigate how to approximate certain values of these functions using periodic…

Dynamical Systems · Mathematics 2007-05-23 Eduardo Garibaldi , Artur O. Lopes

A nearly optimal explicitly-sparse representation for oscillatory kernels is presented in this work by developing a curvelet based method. Multilevel curvelet-like functions are constructed as the transform of the original nodal basis. Then…

Numerical Analysis · Mathematics 2025-04-29 Yanchuang Cao , Jun Liu , Dawei Chen

Finding a maximum cut is a fundamental task in many computational settings. Surprisingly, it has been insufficiently studied in the classic distributed settings, where vertices communicate by synchronously sending messages to their…

Data Structures and Algorithms · Computer Science 2017-07-27 Keren Censor-Hillel , Rina Levy , Hadas Shachnai

Curvelets are efficient to represent highly anisotropic signal content, such as a local linear and curvilinear structure. First-generation curvelets on the sphere, however, suffered from blocking artefacts. We present a new…

Information Theory · Computer Science 2016-11-29 Jennifer Y. H. Chan , Boris Leistedt , Thomas D. Kitching , Jason D. McEwen

We propose a novel framework to produce cartoon videos by fetching the color information from two input keyframes while following the animated motion guided by a user sketch. The key idea of the proposed approach is to estimate the dense…

Computer Vision and Pattern Recognition · Computer Science 2021-01-19 Xiaoyu Li , Bo Zhang , Jing Liao , Pedro V. Sander

We study the problem of approximation of 2D set of points. Such type of problems always occur in physical experiments, econometrics, data analysis and other areas. The often problems of outliers or spikes usually make researchers to apply…

Optimization and Control · Mathematics 2025-02-13 Majid E. Abbasov , Anna I. Belenok

We consider in this paper the optimal approximations of convex univariate functions with feed-forward Relu neural networks. We are interested in the following question: what is the minimal approximation error given the number of…

Machine Learning · Computer Science 2019-09-11 Bo Liu , Yi Liang

A circle $C$ separates two planar sets if it encloses one of the sets and its open interior disk does not meet the other set. A separating circle is a largest one if it cannot be locally increased while still separating the two given sets.…

Computational Geometry · Computer Science 2007-05-23 Jean-Daniel Boissonnat , Jurek Czyzowicz , Olivier Devillers , Jorge Urrutia , Mariette Yvinec

State-of-the-art maximum entropy models for texture synthesis are built from statistics relying on image representations defined by convolutional neural networks (CNN). Such representations capture rich structures in texture images,…

Computer Vision and Pattern Recognition · Computer Science 2022-03-16 Antoine Brochard , Sixin Zhang , Stéphane Mallat

We study the problem of distributed distinct element estimation, where $\alpha$ servers each receive a subset of a universe $[n]$ and aim to compute a $(1+\varepsilon)$-approximation to the number of distinct elements using minimal…

Data Structures and Algorithms · Computer Science 2025-07-01 Ilias Diakonikolas , Daniel M. Kane , Jasper C. H. Lee , Thanasis Pittas , David P. Woodruff , Samson Zhou

Fourier extension is an approximation method that alleviates the periodicity requirements of Fourier series and avoids the Gibbs phenomenon when approximating functions. We describe a similar extension approach using regular wavelet bases…

Numerical Analysis · Mathematics 2020-04-08 Vincent Coppé , Daan Huybrechs

We establish a regularity result for optimal sets of the isoperimetric problem with double density under mild ($\alpha$-)H\"older regularity assumptions on the density functions. Our main Theorem improves some previous results and allows to…

Analysis of PDEs · Mathematics 2023-08-15 Lisa Beck , Eleonora Cinti , Christian Seis

We present simple and practical $(1+\eps)$-approximation algorithm for the Frechet distance between curves. To analyze this algorithm we introduce a new realistic family of curves, $c$-packed curves, that is closed under simplification. We…

Computational Geometry · Computer Science 2012-01-31 Anne Driemel , Sariel Har-Peled , Carola Wenk

The Fr\'echet distance is a commonly used distance measure for curves. Computing the Fr\'echet distance between two polygonal curves of $n$ vertices takes roughly quadratic time, and conditional lower bounds suggest that approximating to…

Computational Geometry · Computer Science 2025-05-09 Thijs van der Horst , Marc van Kreveld , Tim Ophelders , Bettina Speckmann

We provide a new method to approximate a (possibly discontinuous) function using Christoffel-Darboux kernels. Our knowledge about the unknown multivariate function is in terms of finitely many moments of the Young measure supported on the…

Optimization and Control · Mathematics 2021-04-09 Swann Marx , Edouard Pauwels , Tillmann Weisser , Didier Henrion , Jean Lasserre

We consider the problem of improving kernel approximation via randomized feature maps. These maps arise as Monte Carlo approximation to integral representations of kernel functions and scale up kernel methods for larger datasets. Based on…

Machine Learning · Computer Science 2018-10-31 Marina Munkhoeva , Yermek Kapushev , Evgeny Burnaev , Ivan Oseledets

In this paper we deal with the task of uniformly approximating an $L$-biLipschitz curve by means of piecewise linear ones. This is rather simple if one is satisfied to have approximating functions which are $L'$-biLipschitz, for instance…

Classical Analysis and ODEs · Mathematics 2015-05-26 Aldo Pratelli , Emanuela Radici

Using function approximation to represent a value function is necessary for continuous and high-dimensional state spaces. Linear function approximation has desirable theoretical guarantees and often requires less compute and samples than…

Machine Learning · Computer Science 2022-04-27 Michael Beukman , Michael Mitchley , Dean Wookey , Steven James , George Konidaris

A film-like or a thread-like system is a system such that one of its constituting homogeneous phases has a constant thickness $\delta$ or a constant normal section of largest diameter $\delta$. The stick probability function of this phase,…

Materials Science · Physics 2015-11-26 Salvino Ciccariello , Pietro Riello , Alvise Benedetti