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The paper introduces a one dimensional analogy of Poincare's "section" method. Its application to numerical study of sequences of fractional parts is considered. As a result, the possibility of Cantorian structure of time flow is deduced. A…

chao-dyn · Physics 2016-08-31 Ashot Yu. Shahverdian

We study a scalar integro-differential conservation law. The equation was first derived in [2] as the slow erosion limit of granular flow. Considering a set of more general erosion functions, we study the initial boundary value problem for…

Analysis of PDEs · Mathematics 2015-03-17 D. Amadori , W. Shen

We study the statistical properties of the iterates generated by gradient descent, applied to the fundamental problem of least squares regression. We take a continuous-time view, i.e., consider infinitesimal step sizes in gradient descent,…

Machine Learning · Statistics 2019-02-26 Alnur Ali , J. Zico Kolter , Ryan J. Tibshirani

We study the high-frequency limit of non-autonomous gradient flows in metric spaces of energy functionals comprising an explicitly time-dependent perturbation term which might oscillate in a rapid way, but fulfills a certain Lipschitz…

Analysis of PDEs · Mathematics 2016-10-25 Simon Plazotta , Jonathan Zinsl

We consider a general optimal control problem in the setting of gradient flows. Two approximations of the problem are presented, both relying on the variational reformulation of gradient-flow dynamics via the Weighted-Energy-Dissipation…

Optimization and Control · Mathematics 2024-03-25 Takeshi Fukao , Ulisse Stefanelli , Riccardo Voso

We present a general framework for the rigorous numerical analysis of time-fractional nonlinear parabolic partial differential equations, with a fractional derivative of order $\alpha\in(0,1)$ in time. The framework relies on three…

Numerical Analysis · Mathematics 2017-12-05 Bangti Jin , Buyang Li , Zhi Zhou

In this contribution we present an exploratory study of several novel methods for numerical stochastic perturbation theory. For the investigation we consider observables defined through the gradient flow in the simple {\phi}^4 theory.

High Energy Physics - Lattice · Physics 2015-12-29 Mattia Dalla Brida , Marco Garofalo , Anthony D. Kennedy

Over the past few decades, there has been substantial interest in evolution equations that involving a fractional-order derivative of order $\alpha\in(0,1)$ in time, due to their many successful applications in engineering, physics, biology…

Numerical Analysis · Mathematics 2019-01-30 Bangti Jin , Raytcho Lazarov , Zhi Zhou

Convolutional neural networks are widely used in imaging and image recognition. Learning such networks from training data leads to the minimization of a non-convex function. This makes the analysis of standard optimization methods such as…

Optimization and Control · Mathematics 2026-01-14 Jona-Maria Diederen , Holger Rauhut , Ulrich Terstiege

In this paper we investigate the following fractional order in time Cauchy problem \begin{equation*} \begin{cases} \mathbb{D}_{t}^{\alpha }u(t)+Au(t)=f(u(t)), & 1<\alpha <2, u(0)=u_{0},\,\,\,u^{\prime }(0)=u_{1}. & \end{cases}%…

Analysis of PDEs · Mathematics 2018-08-08 Edgardo Alvarez , Ciprian Gal , Valentin Keyantuo , Mahamadi Warma

This paper derives physically meaningful boundary conditions for fractional diffusion equations, using a mass balance approach. Numerical solutions are presented, and theoretical properties are reviewed, including well-posedness and steady…

Analysis of PDEs · Mathematics 2017-06-27 Boris Baeumer , Mihály Kovács , Mark M. Meerschaert , Harish Sankaranarayanan

We initiate an investigation into whether fractional calculus, with its intrinsic long-tailed memory and nonlocal features, can provide a viable model for gravitational-wave memory effects. We consider two toy constructions: ($i$) a…

General Relativity and Quantum Cosmology · Physics 2026-04-01 Sercan Kaya , Bayram Tekin

Time-fractional parabolic equations with a Caputo time derivative are considered. For such equations, we explore and further develop the new methodology of the a-posteriori error estimation and adaptive time stepping proposed in [7]. We…

Numerical Analysis · Mathematics 2023-01-27 Sebastian Franz , Natalia Kopteva

Starting from the microscopic description of a normal fluid in terms of any kind of local interacting many-particle theory we present a well defined step by step procedure to derive the hydrodynamic equations for the macroscopic phenomena.…

Statistical Mechanics · Physics 2022-02-10 Rudolf Haussmann

An initial-boundary value problem with a Caputo time derivative of fractional order $\alpha\in(0,1)$ is considered, solutions of which typically exhibit a singular behaviour at an initial time. For this problem, we give a simple framework…

Numerical Analysis · Mathematics 2018-10-24 Natalia Kopteva

The study of systems with memory requires methods which are different from the methods used in regular dynamics. Systems with power-law memory in many cases can be described by fractional differential equations, which are…

Chaotic Dynamics · Physics 2014-05-20 Mark Edelman

This paper focuses on the convergence problem of the emerging fractional order gradient descent method, and proposes three solutions to overcome the problem. In fact, the general fractional gradient method cannot converge to the real…

Signal Processing · Electrical Eng. & Systems 2022-12-07 Yiheng Wei , Yu Kang , Weidi Yin , Yong Wang

This article overviews how gradient flows, and discretizations thereof, are useful to design and analyze optimization and sampling algorithms. The interplay between optimization, sampling, and gradient flows is an active research area; our…

Computation · Statistics 2023-02-23 N. Garcia Trillos , B. Hosseini , D. Sanz-Alonso

Within the framework of fractional calculus with variable order the evolution of space in the adiabatic limit is investigated. Based on the Caputo definition of a fractional derivative using the fractional quantum harmonic oscillator a…

General Physics · Physics 2013-11-26 R. Herrmann

Fractional derivatives are a well-studied generalization of integer order derivatives. Naturally, for optimization, it is of interest to understand the convergence properties of gradient descent using fractional derivatives. Convergence…

Optimization and Control · Mathematics 2024-06-05 Ashwani Aggarwal