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In this paper we initiate the study of real operator monotonicity for functions of tuples of operators, which are multivariate structured maps with a functional calculus called free functions that preserve the order between real parts (or…

Functional Analysis · Mathematics 2019-12-19 Marcell Gaál , Miklós Pálfia

Consider $d$ disjoint closed subintervals of the unit interval and consider an orientation preserving expanding map which maps each of these subintervals to the whole unit interval. The set of points where all iterates of this expanding map…

Dynamical Systems · Mathematics 2008-02-03 Feliks Przytycki , Folkert Tangerman

This paper studies smoothing properties of the local fractional maximal operator, which is defined in a proper subdomain of the Euclidean space. We prove new pointwise estimates for the weak gradient of the maximal function, which imply…

Functional Analysis · Mathematics 2015-06-17 Toni Heikkinen , Juha Kinnunen , Janne Korvenpää , Heli Tuominen

In this work we study the smoothing effect of some variable coefficient operators of the form $D_t-A$, where $A$ is a Weyl-quantized pseudo-differential operator of order $m=2,3$. The class under consideration includes, among others,…

Analysis of PDEs · Mathematics 2025-11-03 Serena Federico , Davide Tramontana

We study integration and $L_2$-approximation on countable tensor products of function spaces of increasing smoothness. We obtain upper and lower bounds for the minimal errors, which are sharp in many cases including, e.g., Korobov, Walsh,…

Numerical Analysis · Mathematics 2021-09-21 M. Gnewuch , M. Hefter , A. Hinrichs , K. Ritter , G. W. Wasilkowski

Let $X, Y$ be infinite dimensional, Banach spaces. Let $\mathcal{L}(X, Y)$ be the space of bounded operators . Motivated by the fact that smoothness of norm in the higher duals of even order of a Banach space can lead to Frechet…

Functional Analysis · Mathematics 2022-12-13 Taduri Srinivasa Siva Rama Krishna Rao

We study the compactification of nonautonomous systems with autonomous limits and related dynamics. Although the $C^{1}$ extension of the compactification was well established, a great number of problems arising in bifurcation and stability…

Dynamical Systems · Mathematics 2023-12-20 Shuang Chen , Jinqiao Duan

Let us denote ${\cal V}$, the finite dimensional vector spaces of functions of the form $\psi(x) = p_n(x) + f(x) p_m(x)$ where $p_n(x)$ and $p_m(x)$ are arbitrary polynomials of degree at most $n$ and $m$ in the variable $x$ while $f(x)$…

Mathematical Physics · Physics 2007-05-23 Yves Brihaye

Given a symplectic manifold $(M,\omega)$ admitting a metaplectic structure, and choosing a positive $\omega$-compatible almost complex structure $J$ and a linear connection $\nabla$ preserving $\omega$ and $J$, Katharina and Lutz Habermann…

Symplectic Geometry · Mathematics 2015-05-28 Michel Cahen , Simone Gutt , John Rawnsley

For each $q\in{\mathbb{N}}_0$, we construct positive linear polynomial approximation operators $M_n$ that simultaneously preserve $k$-monotonicity for all $0\leq k\leq q$ and yield the estimate \[ |f(x)-M_n(f, x)| \leq c…

Classical Analysis and ODEs · Mathematics 2016-08-02 K. Kopotun , D. Leviatan , A. Prymak , I. A. Shevchuk

We construct and give a complete classification of all the differential symmetry breaking operators D_{{\lambda},{\nu}}^m : C^\infty(S^3, V^3_{\lambda}) \rightarrow C^\infty(S^2,L_{m,{\nu}}), between the spaces of smooth sections of a…

Differential Geometry · Mathematics 2026-05-12 Víctor Pérez-Valdés

We observe that if f is a continuous function on an interval I and x_0 \in I, then f is operator monotone if and only if the function (f(x) - f(x_0)/(x - x_0) is strongly operator convex. Then starting with an operator monotone function…

Functional Analysis · Mathematics 2017-12-25 Lawrence G. Brown

In this paper, we investigate the mapping properties of pseudo-differential operators with operator-valued symbols. Thanks to the smooth atomic decomposition of the operator-valued Triebel-Lizorkin spaces…

Operator Algebras · Mathematics 2018-04-11 Runlian Xia , Xiao Xiong

An analysis of the boundary representations and C$^*$-envelopes of some finite-dimensional operator systems $\mathcal R$ is undertaken by considering relationships between operator-theoretic properties of a $d$-tuple $\mathfrak…

Operator Algebras · Mathematics 2026-01-26 Douglas Farenick , Chi-Kwong Li , Sushil Singla

We recall the notion of a differential operator over a smooth map (in linear and non-linear settings) and consider its versions such as formal $\hbar$-differential operators over a map. We study constructions and examples of such operators,…

Differential Geometry · Mathematics 2020-09-29 Ekaterina Shemyakova , Theodore Voronov

We prove that symplectic cohomology for open convex symplectic manifolds is invariant when the symplectic form undergoes deformations which may be non-exact and non-compactly supported, provided one uses the correct local system of…

Symplectic Geometry · Mathematics 2020-10-01 Gabriele Benedetti , Alexander F. Ritter

We characterize rotation equivariant bounded linear operators from $C(\mathbb{S}^{n-1})$ to $C^2(\mathbb{S}^{n-1})$ by the mass distribution of the spherical Laplacian of their kernel function on small polar caps. Using this…

Metric Geometry · Mathematics 2023-02-27 Leo Brauner , Oscar Ortega-Moreno

We construct examples of $C^\infty$ smooth submanifolds in ${\Bbb C}^n$ and ${\Bbb R}^n$ of codimension 2 and 1, which intersect every complex, respectively real, analytic curve in a discrete set. The examples are realized either as compact…

Complex Variables · Mathematics 2007-05-23 Dan Coman , Norman Levenberg , Evgeny A. Poletsky

We study continuity and boundedness of order-to-topology bounded and order-to topology continuous operators from ordered to topological vector spaces. Several results on automatic continuity of operators from ordered Frechet spaces to…

Functional Analysis · Mathematics 2026-04-21 Eduard Emelyanov , Svetlana Gorokhova

It is well known that elliptic operators on a smooth compact manifold are classified by K-homology. We prove that a similar classification is also valid for manifolds with simplest singularities: isolated conical points and fibered…

Operator Algebras · Mathematics 2007-05-23 A. Savin