Stereographic compactification and affine bi-Lipschitz homeomorphisms ...

Let $σ_q : \mathbb{R}^q \to {\bf S}^q \setminus N_q$ be the inverse of the stereographic projection with centre the north pole $N_q$. Let $W_i$ be a closed subset of $\mathbb{R}^{q_i}$, for $i=1,2$. Let $Φ:W_1 \to W_2$ be a bi-Lipschitz homeomorphism. The main result states that the homeomorphism $σ...

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Bibliographic Details
Main Authors: Grandjean, Vincent, Oliveira, Roger
Format: Text
Language:unknown
Published: arXiv 2023
Subjects:
Online Access:https://dx.doi.org/10.48550/arxiv.2305.07469
https://arxiv.org/abs/2305.07469
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Summary:Let $σ_q : \mathbb{R}^q \to {\bf S}^q \setminus N_q$ be the inverse of the stereographic projection with centre the north pole $N_q$. Let $W_i$ be a closed subset of $\mathbb{R}^{q_i}$, for $i=1,2$. Let $Φ:W_1 \to W_2$ be a bi-Lipschitz homeomorphism. The main result states that the homeomorphism $σ_{q_2}\circ Φ\circ σ_{q_1}^{-1}$ is a bi-Lipschitz homeomorphism, extending bi-Lipschitz-ly at $N_{q_1}$ with value $N_{q_2}$ whenever $W_1$ is unbounded. As two straightforward applications in the polynomially bounded o-minimal context over the real numbers, we obtain for free a version at infinity of: 1) Sampaio's tangent cone result; 2) Links preserving re-parametrization of definable bi-Lipschitz homeomorphisms of Valette. ... : 15 pages ...