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In this paper, we consider the asymptotical regularization with convex constraints for nonlinear ill-posed problems. The method allows to use non-smooth penalty terms, including the L1-like and the total variation-like penalty functionals,…

Numerical Analysis · Mathematics 2022-03-23 Min Zhong , Wei Wang

In this paper, we introduce an iterative numerical method to solve systems of nonlinear equations. The third-order convergence of this method is analyzed. Several examples are given to illustrate the efficiency of the proposed method.

Dynamical Systems · Mathematics 2009-04-23 M. Eshaghi Gordji , A. Ebadian , M. B. Ghaemi , J. Shokri

In this paper we deal with an equation in nonlinear combination of iterates. Although it can be reduced by the logarithm conjugacy to a form for application of Schauder's or Banach's fixed point theorems, a difficulty called Zero Problem is…

Dynamical Systems · Mathematics 2024-01-15 Chaitanya Gopalakrishna , Weinian Zhang

The Cauchy problem for fractional derivatives linear systems of ordinary differential equations with constant coefficients is considered, where at first the analytic expressions are given through the matrix exponent of its corresponding…

Dynamical Systems · Mathematics 2018-05-18 Fikret A. Aliev , N. A. Aliev , N. A. Safarova , K. G. Kasimova , N. I Velieva

In this paper, we study the inverse problem for a class of abstract ultraparabolic equations which is well-known to be ill-posed. We employ some elementary results of semi-group theory to present the formula of solution, then show the…

Analysis of PDEs · Mathematics 2015-12-10 Vo Anh Khoa , Le Trong Lan , Nguyen Huy Tuan , Tran The Hung

The compact explicit expressions for formal exact operator solutions to Cauchy problem for sufficiently general systems of nonlinear differential equations (ODEs and PDEs) in the form of chronological operator exponents are given. The…

Mathematical Physics · Physics 2009-10-21 Yu. N. Kosovtsov

We investigate a class of scalar conservation laws on manifolds driven by multiplicative Gaussian (Ito) noise. The Cauchy problem defined on a Riemannian manifold is shown to be well-posed. We prove existence of generalized kinetic…

Analysis of PDEs · Mathematics 2019-06-28 Luca Galimberti , Kenneth H. Karlsen

In this article, we initiate the study of the Cauchy problem for the two-dimensional relativistic Euler equations in a low-regularity setting. By introducing good variables--a rescaled velocity, logarithmic enthalpy, and an appropriately…

Analysis of PDEs · Mathematics 2025-12-19 Huali Zhang

An unsteady problem is considered for a space-fractional equation in a bounded domain. A first-order evolutionary equation involves the square root of an elliptic operator of second order. Finite element approximation in space is employed.…

Numerical Analysis · Mathematics 2015-10-29 Petr N. Vabishchevich

In this paper we revisit the classical Cauchy problem for Laplace's equation as well as two further related problems in the light of regularisation of this highly ill-conditioned problem by replacing integer derivatives with fractional…

Numerical Analysis · Mathematics 2023-09-26 Barbara Kaltenbacher an William Rundell

Regularization is a core component of modern inverse problems, as it helps establish the well-posedness of the solution of interest. Popular regularization approaches include variational regularization and iterative regularization. The…

Optimization and Control · Mathematics 2025-08-08 Jie Gao , Cesare Molinari , Silvia Villa , Jingwei Liang

Modelling real world systems frequently requires the solution of systems of nonlinear equations. A number of approaches have been suggested and developed for this computational problem. However, it is also possible to attempt solutions…

Computation · Statistics 2025-01-07 John C. Nash , Ravi Varadhan

This work unifies the analysis of various randomized methods for solving linear and nonlinear inverse problems by framing the problem in a stochastic optimization setting. By doing so, we show that many randomized methods are variants of a…

Numerical Analysis · Mathematics 2023-06-21 Jonathan Wittmer , C. G. Krishnanunni , Hai V. Nguyen , Tan Bui-Thanh

We study the Cauchy problem for a system of cubic nonlinear Klein-Gordon equations in one space dimension. Under a suitable structural condition on the nonlinearity, we will show that the solution exists globally and decays of the order…

Analysis of PDEs · Mathematics 2016-02-11 Donghyun Kim

Inverse problems are in many cases solved with optimization techniques. When the underlying model is linear, first-order gradient methods are usually sufficient. With nonlinear models, due to nonconvexity, one must often resort to…

Numerical Analysis · Mathematics 2023-05-15 Arttu Arjas , Mikko J. Sillanpää , Andreas Hauptmann

A general formalism to solve nonlinear differential equations is given. Solutions are found and reduced to those of second order nonlinear differential equations in one variable. The approach is uniformized in the geometry and solves…

General Physics · Physics 2007-05-23 Gordon Chalmers

In this paper we investigate an adaptive discretization strategy for ill-posed linear prob- lems combined with a regularization from a class of semiiterative methods. We show that such a discretization approach in combination with a…

Numerical Analysis · Mathematics 2014-07-22 Wolfgang Erb , Evgeniya V. Semenova

In this paper we study a Cauchy problem for the nonlinear damped wave equations for a general positive operator with discrete spectrum. We derive the exponential in time decay of solutions to the linear problem with decay rate depending on…

Analysis of PDEs · Mathematics 2017-12-15 Michael Ruzhansky , Niyaz Tokmagambetov

In this paper we prove the global existence and uniqueness of the low regularity solutions to the Cauchy problem of quasi-linear wave equations with radial symmetric initial data in three space dimensions. The results are based on the…

Analysis of PDEs · Mathematics 2007-05-23 Yi Zhou , Zhen Lei

In this article, we prove various illposedness results for the Cauchy problem for the incompressible Hall- and electron-magnetohydrodynamic (MHD) equations without resistivity. These PDEs are fluid descriptions of plasmas, where the effect…

Analysis of PDEs · Mathematics 2021-01-07 In-Jee Jeong , Sung-Jin Oh