Results 51 to 60 of about 837 (138)

Beyond Gevrey regularity

open access: yes, 2016
We define and study classes of smooth functions which are less regular than Gevrey functions. To that end we introduce two-parameter dependent sequences which do not satisfy Komatsu's condition (M.2)', which implies stability under differential operators
Pilipović, Stevan   +2 more
core   +1 more source

About spaces of $\omega_1$-$\omega_2$-ultradifferentiable functions

open access: yesBulletin of the Belgian Mathematical Society - Simon Stevin, 2008
Nonisotropic spaces of ultradifferentiable functions are introduced on products \( \Omega_1 \times \Omega_2 \subset \mathbb R^r \times \mathbb R^s \) in such a way that the first \(r\) partial derivatives are governed by a weight function \( \omega_1 \) in the sense of \textit{R.\,W.\thinspace Braun, R.\,Meise} and \textit{B.\,A.\thinspace Taylor ...
Schmets, Jean, Valdivia, Manuel
openaire   +3 more sources

Construction of the log‐convex minorant of a sequence {Mα}α∈N0d$\lbrace M_\alpha \rbrace _{\alpha \in \mathbb {N}_0^d}$

open access: yesMathematische Nachrichten, Volume 298, Issue 2, Page 456-477, February 2025.
Abstract We give a simple construction of the log‐convex minorant of a sequence {Mα}α∈N0d$\lbrace M_\alpha \rbrace _{\alpha \in \mathbb {N}_0^d}$ and consequently extend to the d$d$‐dimensional case the well‐known formula that relates a log‐convex sequence {Mp}p∈N0$\lbrace M_p\rbrace _{p\in \mathbb {N}_0}$ to its associated function ωM$\omega _M$, that
Chiara Boiti   +3 more
wiley   +1 more source

Extension of ultradifferentiable functions

open access: yesManuscripta Mathematica, 1994
The extension problem considered in this paper is of the type given below: Let \(K_1\) and \(K\) be compact convex sets such that \(\text{int} (K_1) \supset K\), and such that \(\text{int} (K)\neq \emptyset\) or \(K= \{0\}\) and let a sequence \((N_a)\) of positive numbers be given.
openaire   +1 more source

The Metivier inequality and ultradifferentiable hypoellipticity

open access: yesMathematische Nachrichten, Volume 297, Issue 7, Page 2517-2531, July 2024.
Abstract In 1980, Métivier characterized the analytic (and Gevrey) hypoellipticity of L2$L^2$‐solvable partial linear differential operators by a priori estimates. In this note, we extend this characterization to ultradifferentiable hypoellipticity with respect to Denjoy–Carleman classes given by suitable weight sequences. We also discuss the case when
Paulo D. Cordaro, Stefan Fürdös
wiley   +1 more source

Optimal embeddings of ultradistributions into differential algebras

open access: yes, 2017
We construct embeddings of spaces of non-quasianalytic ultradistributions into differential algebras enjoying optimal properties in view of a Schwartz type impossibility result, also shown in this article. We develop microlocal analysis in these algebras
Debrouwere, Andreas   +2 more
core   +2 more sources

An Introduction to Extended Gevrey Regularity

open access: yesAxioms
Gevrey classes are the most common choice when considering the regularities of smooth functions that are not analytic. However, in various situations, it is important to consider smoothness properties that go beyond Gevrey regularity, for example, when ...
Nenad Teofanov   +2 more
doaj   +1 more source

The surjectivity of the Borel mapping in the mixed setting for ultradifferentiable ramification spaces

open access: yes, 2019
We consider r-ramification ultradifferentiable classes, introduced by J. Schmets and M. Valdivia in order to study the surjectivity of the Borel map, and later on also exploited by the authors in the ultraholomorphic context.
Jiménez-Garrido, Javier   +2 more
core   +1 more source

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