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The existence of singularities of the solution for a class of Lax equations is investigated using a development of the fac- torization method first proposed by Semenov-Tian-Shansky and Reymann [11], [9]. It is shown that the existence of a…

Dynamical Systems · Mathematics 2010-10-15 António F. dos Santos , Pedro F. dos Santos

We consider several notions of regularity, including strong regularity, bounded relative units, and Ditkin's condition, in the setting of vector-valued function algebras. Given a commutative Banach algebra $A$ and a compact space $X$, let…

Functional Analysis · Mathematics 2023-02-16 Z. Barqi , M. Abtahi

This paper focuses on the problem of reconstructing a vector of rational functions given some evaluations, or more generally given their remainders modulo different polynomials. The special case of rational functions sharing the same…

Symbolic Computation · Computer Science 2020-02-21 Eleonora Guerrini , Romain Lebreton , Ilaria Zappatore

In this paper, we combine tools from pluripotential theory and commutative algebra to study singularity invariants of plurisubharmonic functions. We establish several relationships between the singularity invariants of plurisubharmonic…

Complex Variables · Mathematics 2025-05-28 Pham Hoang Hiep

We establish existence results for a class of mixed anisotropic and nonlocal $p$-Laplace equation with singular nonlinearities. We consider both constant and variable singular exponents. Our argument is based on an approximation method. To…

Analysis of PDEs · Mathematics 2023-03-28 Prashanta Garain , Wontae Kim , Juha Kinnunen

Foundations of the formal series $*$ -- calculus in deformation quantisation are discussed. Several classes of continuous linear functionals over algebras applied in classical and quantum physics are introduced. The notion of nonnegativity…

Quantum Physics · Physics 2019-02-08 Jaromir Tosiek , Michał Dobrski

This article deals with the study of the following nonlinear doubly nonlocal equation: \begin{equation*} (-\Delta)^{s_1}_{p}u+\ba(-\Delta)^{s_2}_{q}u = \la a(x)|u|^{\delta-2}u+ b(x)|u|^{r-2} u,\; \text{ in }\; \Om, \; u=0 \text{ on }…

Analysis of PDEs · Mathematics 2019-02-04 Divya Goel , Deepak Kumar , K. Sreenadh

In the process of proving a sharpened form of G\r{a}rding's inequality, Fefferman & Phong demonstrated that every non-negative function $f\in C^{3,1}(\mathbb{R}^n)$ can be written as a finite sum of squares of functions in…

Functional Analysis · Mathematics 2023-03-15 Sullivan F. MacDonald

We consider Nehari's problem in the case of non-uniqueness of solution. The solution set is then parametrized by the unit ball of $H^{\infty}$ by means of so-called {\em regular generators} -- bounded holomorphic functions $\phi$. The…

Mathematical Physics · Physics 2008-03-18 A. Volberg , P. Yuditskii

In this paper we obtain interior regularity estimates for viscosity solutions of nonlocal Dirichlet problems that degenerate when the gradient of the solution vanishes. Interior H\"older estimates are obtained when the order of the…

Analysis of PDEs · Mathematics 2020-04-08 Disson Dos Prazeres , Erwin Topp

Recently, new classes of positive and measurable functions, $\mathcal{M}(\rho)$ and $\mathcal{M}(\pm \infty)$, have been defined in terms of their asymptotic behaviour at infinity, when normalized by a logarithm (Cadena et al., 2015, 2016,…

Classical Analysis and ODEs · Mathematics 2017-06-30 Meitner Cadena , Marie Kratz , Edward Omey

The regularity theory of the Campanato space $\mathcal{L}^{(q,\lambda)}_k(\Omega)$ has found many applications within the regularity theory of solutions to various geometric variational problems. Here we extend this theory from…

Differential Geometry · Mathematics 2022-10-13 Paul Minter

For the class of de Branges-Rovnyak spaces $\mathcal{H}(b)$ of the unit disk $\mathbb{D}$ defined by extreme points $b$ of the unit ball of $H^\infty$, we study the problem of approximation of a general function in $\mathcal{H}(b)$ by a…

Functional Analysis · Mathematics 2021-08-20 Adem Limani , Bartosz Malman

We obtain sharp estimates for a generalized Zalcman coefficient functional with a complex parameter for the Hurwitz class and the Noshiro-Warschawski class of univalent functions as well as for the closed convex hulls of the convex and…

Complex Variables · Mathematics 2018-10-31 Iason Efraimidis , Dragan Vukotić

We explain how a classical theorem by Arnol'd and Melrose on non-singular functions on a symplectic manifold with boundary can be proved in few lines, and we use the same method to obtain a new result, which is a normal form with functional…

Symplectic Geometry · Mathematics 2018-08-21 Konstantinos Kourliouros , Michail Zhitomirskii

Modelling of singularities given by discontinuous functions or distributions by means of generalized functions has proved useful in many problems posed by physical phenomena. We introduce in a systematic way generalized functions of…

Functional Analysis · Mathematics 2013-05-31 Blagovest Damyanov

We investigate the regularity of the viscosity solutions to a class of degenerate/singular fully nonlinear elliptic equations with Hamiltonian terms. To overcome the difficulty caused by the simultaneous presence of the general…

Analysis of PDEs · Mathematics 2026-05-05 Wentao Huo , Xiaofeng Jin , Lingwei Ma , Zhenqiu Zhang

We prove continuity for bounded weak solutions of a nonlinear nonlocal parabolic type equation associated to a Dirichlet form with a rough kernel. The equation is allowed to be singular at the level zero, and solutions may change sign. If…

Analysis of PDEs · Mathematics 2017-10-09 Arturo de Pablo , Fernando Quirós , Ana Rodríguez

Despite the many applications of rate-independent systems, their regularity theory is still largely unexplored. Usually, only weak solution with potentially very low regularity are considered, which requires non-smooth techniques. In this…

Analysis of PDEs · Mathematics 2016-03-01 Filip Rindler , Sebastian Schwarzacher

The asymptotic Samuel function generalizes to arbitrary rings the usual order function of a regular local ring. Here we explore some natural properties in the context of excellent, equidimensional rings containing a field. In addition, we…

Commutative Algebra · Mathematics 2025-05-28 A. Bravo , S. Encinas , J. Guillán-Rial