dorsal/arxiv
View SchemaAsymptotic-M\"obius maps
| Authors | Georg Grützner |
|---|---|
| Categories | |
| ArXiv ID | 2601.07702vv1 |
| URL | https://arxiv.org/abs/2601.07702 |
| License | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
Abstract
We introduce asymptotic-M\"obius (AM) maps, a large-scale analogue of quasi-M\"obius maps tailored to geometric group theory. AM-maps capture coarse cross-ratio behavior for configurations of points that lie far apart, providing a notion of "conformality at infinity" that is stable under quasi-isometries, compatible with scaling limits, and rigid enough to yield structural consequences absent from Pansu's notion of large-scale conformality. We establish basic properties of AM-maps, give several sources of examples, including quasi-isometries, sublinear bi-Lipschitz equivalences, snowflaking, and Assouad embeddings, and apply the theory to large-scale dimension and metric cotype. As applications we obtain dimension-monotonicity results for nilpotent groups and CAT(0) spaces, and new obstructions to the existence of AM-maps arising from metric cotype.
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"abstract": "We introduce asymptotic-M\\\"obius (AM) maps, a large-scale analogue of quasi-M\\\"obius maps tailored to geometric group theory. AM-maps capture coarse cross-ratio behavior for configurations of points that lie far apart, providing a notion of \"conformality at infinity\" that is stable under quasi-isometries, compatible with scaling limits, and rigid enough to yield structural consequences absent from Pansu\u0027s notion of large-scale conformality. We establish basic properties of AM-maps, give several sources of examples, including quasi-isometries, sublinear bi-Lipschitz equivalences, snowflaking, and Assouad embeddings, and apply the theory to large-scale dimension and metric cotype. As applications we obtain dimension-monotonicity results for nilpotent groups and CAT(0) spaces, and new obstructions to the existence of AM-maps arising from metric cotype.",
"arxiv_id": "2601.07702",
"authors": [
"Georg Gr\u00fctzner"
],
"categories": [
"math.MG"
],
"license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
"title": "Asymptotic-M\\\"obius maps",
"url": "https://arxiv.org/abs/2601.07702",
"version": "v1"
},
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