activity
20032026
most citedComposition in ultradifferentiable classes

62 citations · 389 across the 51 of their papers we have counts for

collaborators

57 papers

math.CA2026

Natural reparameterization and continuity of the solution map for polynomials

Adam Parusiński, Armin Rainer

The optimal Sobolev regularity of the roots of a smooth curve of monic complex polynomials is , for , where is the degree. This result is stab…

math.FA2023

Perturbation theory of polynomials and linear operators

Adam Parusiński, Armin Rainer

This survey revolves around the question how the roots of a monic polynomial (resp. the spectral decomposition of a linear operator), whose coefficients depend in a smooth way on p…

math.LO2023★ 1 cited

Uniform extension of definable -Whitney jets

Adam Parusiński, Armin Rainer

We show that definable Whitney jets of class , where is a nonnegative integer and is a modulus of continuity, are the restrictions of definable -functions…

math.LO2023

Definable Lipschitz selections for affine-set valued maps

Adam Parusiński, Armin Rainer

Whitney's extension problem, i.e., how one can tell whether a function , , is the restriction of a -function on , wa…

math.FA2022

Quantitative tame properties of differentiable functions with controlled derivatives

Armin Rainer

We show that differentiable functions, defined on a convex body , whose derivatives do not exceed a suitable given sequence of positive real numbers share…

math.FA2022★ 3 cited

The Borel map in the mixed Beurling setting

David Nicolas Nenning, Armin Rainer, Gerhard Schindl

The Borel map takes a smooth function to its infinite jet of derivatives (at zero). We study the restriction of this map to ultradifferentiable classes of Beurling type in a very g…