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arXiv · 2508.17956

Geometric properties of a new hyperbolic type metric

Xinyu Chen·Xiaohui Zhang
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Abstract

We introduce a new distance function \(\tilde{S}_{G,c}\) in a metric space \((X,d)\), defined by \[ \tilde{S}_{G,c}(x,y)=\log\left(1+\frac{c\,d(x,y)}{\sqrt{1+d(x,G)}\sqrt{1+d(y,G)}}\right) \] for \(x, y \in X\), where \(c\) is a positive real number and \(d(x,G)\) denotes the distance from \(x\) to the subset \(G \subset X\). We establish that \(\tilde{S}_{G,c}\) is a metric for \(c \geq 2\). Moreover, we show that the condition \(c \geq 2\) is sharp. This paper investigates geometric properties of the metric \(\tilde{S}_{G,c}\), including comparison inequalities with the triangular ratio metric and inclusion relations among metric balls. We demonstrate the quasiconformality of bilipschitz mappings with respect to \(\tilde{S}_{G,c}\) and study the distortion property of the metric \(\tilde{S}_{\partial\mathbb{B}^{n},c}\) under M\"obius transformations of the unit ball.

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Xinyu Chen, Xiaohui Zhang. 2025-08-25. Geometric properties of a new hyperbolic type metric. https://arxiv.org/abs/2508.17956

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