Construction of the log-convex minorant of a sequence $\{M_α\}_{α\in\mathbb{N}_0^d}$

Fuente: arXiv
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Main Authors: Boiti, Chiara, Jornet, David, Oliaro, Alessandro, Schindl, Gerhard
Format: Preprint
Published: 2024
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_version_ 1866909492405338112
author Boiti, Chiara
Jornet, David
Oliaro, Alessandro
Schindl, Gerhard
author_facet Boiti, Chiara
Jornet, David
Oliaro, Alessandro
Schindl, Gerhard
contents We give a simple construction of the log-convex minorant of a sequence $\{M_α\}_{α\in\mathbb{N}_0^d}$ and consequently extend to the $d$-dimensional case the well-known formula that relates a log-convex sequence $\{M_p\}_{p\in\mathbb{N}_0}$ to its associated function $ω_M$, that is $M_p=\sup_{t>0}t^p\exp(-ω_M(t))$. We show that in the more dimensional anisotropic case the classical log-convex condition $M_α^2\leq M_{α-e_j}M_{α+e_j}$ is not sufficient: convexity as a function of more variables is needed (not only coordinate-wise). We finally obtain some applications to the inclusion of spaces of rapidly decreasing ultradifferentiable functions in the matrix weighted setting.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11245
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Construction of the log-convex minorant of a sequence $\{M_α\}_{α\in\mathbb{N}_0^d}$
Boiti, Chiara
Jornet, David
Oliaro, Alessandro
Schindl, Gerhard
Functional Analysis
40B05, 46A13, 46A45
We give a simple construction of the log-convex minorant of a sequence $\{M_α\}_{α\in\mathbb{N}_0^d}$ and consequently extend to the $d$-dimensional case the well-known formula that relates a log-convex sequence $\{M_p\}_{p\in\mathbb{N}_0}$ to its associated function $ω_M$, that is $M_p=\sup_{t>0}t^p\exp(-ω_M(t))$. We show that in the more dimensional anisotropic case the classical log-convex condition $M_α^2\leq M_{α-e_j}M_{α+e_j}$ is not sufficient: convexity as a function of more variables is needed (not only coordinate-wise). We finally obtain some applications to the inclusion of spaces of rapidly decreasing ultradifferentiable functions in the matrix weighted setting.
title Construction of the log-convex minorant of a sequence $\{M_α\}_{α\in\mathbb{N}_0^d}$
topic Functional Analysis
40B05, 46A13, 46A45
url https://arxiv.org/abs/2401.11245