Quantitative estimates for fractional Sobolev mappings in rational homotopy groups

Fuente: arXiv
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Main Authors: Park, Woongbae, Schikorra, Armin
Format: Preprint
Published: 2022
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author Park, Woongbae
Schikorra, Armin
author_facet Park, Woongbae
Schikorra, Armin
contents Let $\mathcal{N} \subset \mathbb{R}^M$ be a smooth simply connected compact manifold without boundary. A rational homotopy subgroup of $π_{N}(\mathcal{N})$ is represented by a homomorphism \[{\rm deg}: π_{N}(\mathcal{N}) \to \mathbb{R}.\] For maps $f: \mathbb{S}^N \to \mathcal{N}$ we give a quantitative estimate of its rational homotopy group element ${\rm deg}([f]) \in \mathbb{R}$ in terms of its fractional Sobolev-norm or Hölder norm. That is, we show that for all $β\in (β_0({\rm deg}),1]$, \[ |{\rm deg}([f])|\leq C({\rm deg})\, [f]_{W^{β,\frac{N}β}(\mathbb{S}^N)}^{\frac{N+L({\rm deg})}β}, \] and \[ |{\rm deg}([f])|\leq C({\rm deg})\, [f]_{C^β(\mathbb{S}^N)}^{\frac{N+L({\rm deg})}β}. \] Here $C({\rm deg}) > 0$, $L({\rm deg}) \in \mathbb{N}$, $β_0({\rm deg}) \in (0,1)$ are computable from the rational homotopy group represented by ${\rm deg}$. This extends earlier work by Van Schaftingen and the second author on the Hopf degree to the Novikov's integral representation for rational homotopy groups as developed by Sullivan, Novikov, Hardt and Rivière.
format Preprint
id arxiv_https___arxiv_org_abs_2207_04207
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Quantitative estimates for fractional Sobolev mappings in rational homotopy groups
Park, Woongbae
Schikorra, Armin
Analysis of PDEs
Algebraic Topology
Functional Analysis
Let $\mathcal{N} \subset \mathbb{R}^M$ be a smooth simply connected compact manifold without boundary. A rational homotopy subgroup of $π_{N}(\mathcal{N})$ is represented by a homomorphism \[{\rm deg}: π_{N}(\mathcal{N}) \to \mathbb{R}.\] For maps $f: \mathbb{S}^N \to \mathcal{N}$ we give a quantitative estimate of its rational homotopy group element ${\rm deg}([f]) \in \mathbb{R}$ in terms of its fractional Sobolev-norm or Hölder norm. That is, we show that for all $β\in (β_0({\rm deg}),1]$, \[ |{\rm deg}([f])|\leq C({\rm deg})\, [f]_{W^{β,\frac{N}β}(\mathbb{S}^N)}^{\frac{N+L({\rm deg})}β}, \] and \[ |{\rm deg}([f])|\leq C({\rm deg})\, [f]_{C^β(\mathbb{S}^N)}^{\frac{N+L({\rm deg})}β}. \] Here $C({\rm deg}) > 0$, $L({\rm deg}) \in \mathbb{N}$, $β_0({\rm deg}) \in (0,1)$ are computable from the rational homotopy group represented by ${\rm deg}$. This extends earlier work by Van Schaftingen and the second author on the Hopf degree to the Novikov's integral representation for rational homotopy groups as developed by Sullivan, Novikov, Hardt and Rivière.
title Quantitative estimates for fractional Sobolev mappings in rational homotopy groups
topic Analysis of PDEs
Algebraic Topology
Functional Analysis
url https://arxiv.org/abs/2207.04207