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We show that interpolation results in the $S$-nodes theory may be considered as Khrushchev-type formulas. If separation of the well-known Verblunsky (Schur) coefficients occurs in Khrushchev formulas, the separation of the so the called new…

Classical Analysis and ODEs · Mathematics 2024-07-16 Alexander Sakhnovich

We give precise conditions under which the real interpolation space [Y_0,X_1]_{s,p} coincides with a closed subspace of the corresponding interpolation space [X_0,X_1]_{s,p} when Y_0 is a closed subspace of X_0 of codimension one. This…

Functional Analysis · Mathematics 2007-05-23 S. Ivanov , N. Kalton

We design quasi-interpolation operators based on piecewise polynomial weight functions of degree less than or equal to $p$ that map into the space of continuous piecewise polynomials of degree less than or equal to $p+1$. We show that the…

Numerical Analysis · Mathematics 2024-04-23 Thomas Führer , Manuel A. Sánchez

We show that finitely subgraded Lie algebras of compact operators have invariant subspaces when conditions of quasinilpotence are imposed on certain components of the subgrading. This allows us to obtain some useful information about the…

Operator Algebras · Mathematics 2010-01-20 Matthew Kennedy , Victor Shulman , Yuri Turovskii

We prove the version of interpolation theorem for non-commutative vector-valued fully symmetric spaces associated with fully symmetric Banach function spaces and a von Neumann algebra equipped with a faithful semifinite normal trace.

Operator Algebras · Mathematics 2013-11-26 V. I. Chilin , A. K. Karimov

We study interpolation properties for Shavrukov's bimodal logic $\mathbf{GR}$ of usual and Rosser provability predicates. For this purpose, we introduce a new sublogic $\mathbf{GR}^\circ$ of $\mathbf{GR}$ and its relational semantics. Based…

Logic · Mathematics 2023-11-20 Haruka Kogure , Taishi Kurahashi

Peak interpolation is concerned with a foundational kind of mathematical task: building functions in a fixed algebra $A$ which have prescribed values or behaviour on a fixed closed subset (or on several disjoint subsets). In this paper we…

Operator Algebras · Mathematics 2014-02-26 David P. Blecher

In this paper, we study functional approximations where we choose the so-called radial basis function method and more specifically, quasi-interpolation. From the various available approaches to the latter, we form new quasi-Lagrange…

Numerical Analysis · Mathematics 2023-09-07 Martin Buhmann , Janin Jäger , Joaquín Jódar , Miguel L. Rodríguez

We show that for integral operators of general form the norm bounds in Lorentz spaces imply certain norm bounds for the maximal function. As a consequence, the a.e. convergence for the integral operators on the Lorentz spaces follows from…

Classical Analysis and ODEs · Mathematics 2008-02-03 Alexander Kiselev

Let $\Lambda \subset R$ be a strictly increasing sequence. For $r = 1,2$, we give a simple explicit expression for an equivalent norm on the trace spaces $W_p^r(R)|_\Lambda$, $L_p^r(R)|_\Lambda$ of the non-homogeneous and homogeneous…

Functional Analysis · Mathematics 2014-01-21 Daniel Estévez

We show interior Schauder estimates for a special class of fully nonlinear parabolic Isaacs equations by the maximum principle, providing an Evans-Krylov result for the model equation $\min\{\inf_{\beta}L_\beta u,\sup_\gamma L_\gamma…

Analysis of PDEs · Mathematics 2026-01-19 Alessandro Goffi

We investigate properties of function spaces induced by the inner product Sobolev spaces $H^{s}(\Omega)$ over a bounded Euclidean domain $\Omega$ and by an elliptic differential operator $A$ on $\overline{\Omega}$. The domain and the…

Analysis of PDEs · Mathematics 2020-07-28 Tetiana Kasirenko , Vladimir Mikhailets , Aleksandr Murach

The aim of this paper is to characterize universal and multiplier interpolating sequences for de Branges-Rovnyak spaces H (b) where the defining function b is a general non-extreme rational function. Our results carry over to recently…

Complex Variables · Mathematics 2025-12-11 Andreas Hartmann , Giuseppe Lamberti

We consider quasi-interpolation with a main application in radial basis function approximations and compression in this article. Constructing and using these quasi-interpolants, we consider wavelet and compression-type approximations from…

Numerical Analysis · Mathematics 2024-07-09 Martin Buhmann , Feng Dai

A full interpolation theory for Sobolev functions with smoothness between 0 and 1 and vanishing trace on a part of the boundary of an open set is established. Geometric assumptions are of mostly measure theoretic nature and reach beyond…

Classical Analysis and ODEs · Mathematics 2021-02-23 Sebastian Bechtel , Moritz Egert

Gromov has shown how to construct holomorphic maps of the plane to a complex manifold with prescribed values on a lattice. In the present paper, a similar interpolation theorem for pseudo-holomorphic maps from the cylinder S to an…

Differential Geometry · Mathematics 2010-06-10 Antoine Gournay

An extension of Marcinkiewicz Interpolation Theorem, allowing intermediate spaces of Orlicz type, is proved. This generalization yields a necessary and sufficient condition so that every quasilinear operator, which maps the set, $S(X,\mu)$,…

Classical Analysis and ODEs · Mathematics 2017-11-28 Ron Kerman , Rama Rawat , Rajesh K. Singh

The Rademacher series in rearrangement invariant function spaces "closed" to the space L_\infty are considered. In terms of interpolation theory of operators a correspondence between such spaces and spaces of coefficients generated by them…

Functional Analysis · Mathematics 2007-05-23 S. V. Astashkin

We prove invariant Harnack inequalities for certain classes of non-divergence form equations of Kolmogorov type. The operators we consider exhibit invariance properties with respect to a homogeneous Lie group structure. The coefficient…

Analysis of PDEs · Mathematics 2019-03-08 Farhan Abedin , Giulio Tralli

Elliptic and parabolic integro-differential model problems are considered in the whole space. By verifying H\"ormander condition, the existence and uniqueness is proved in L_{p}-spaces of functions whose regularity is defined by a scalable,…

Analysis of PDEs · Mathematics 2016-05-24 R. Mikulevicius , C. Phonsom