Ending currents of hyperbolic group actions
Abstract
We develop a theory of ending currents for properly discontinuous isometric actions of hyperbolic groups on Gromov hyperbolic spaces, generalizing Thurston's ending laminations. Several natural generalizations are considered, which agree in the 3-dimensional hyperbolic setting but are otherwise distinct. We illustrate these invariants and their differences by several examples, including closed surface group actions on hyperbolic group extensions arising from Teichmüller theory and a geometrically finite action of a closed surface group on ℍ4 with a single cusp that corresponds to a non-simple curve on the surface. We also discuss the conditions under which ending currents characterize geometrically finite actions, obtaining several equivalent conditions and some surprises, illustrated by an example of a geometrically infinite action whose ending currents are all supported on a single orbit of peripheral subgroups.
Related
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- Uniformly Lipschitz Hyperbolic Group Actions on ℓp
- Convex hulls and area minimizing currents in asymptotically locally hyperbolic manifolds
- Recognizing convergence actions as proper isometric actions on hyperbolic spaces
- Random Quotients of Hyperbolic Spaces with Respect to WPD Actions and Linear Connectivity of the Boundary
BibTeX
@misc{minsky2026ending,
title = {{Ending currents of hyperbolic group actions}},
author = {Yair Minsky and Tianqi Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18887},
eprint = {2610.18887},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.18887},
}
RIS
TY - UNPB
TI - Ending currents of hyperbolic group actions
AU - Yair Minsky
AU - Tianqi Wang
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.18887
UR - https://arxiv.org/abs/2610.18887
AB - We develop a theory of ending currents for properly discontinuous isometric actions of hyperbolic groups on Gromov hyperbolic spaces, generalizing Thurston's ending laminations. Several natural generalizations are considered, which agree in the 3-dimensional hyperbolic setting but are otherwise distinct. We illustrate these invariants and their differences by several examples, including closed surface group actions on hyperbolic group extensions arising from Teichmüller theory and a geometrically finite action of a closed surface group on ℍ^4 with a single cusp that corresponds to a non-simple curve on the surface. We also discuss the conditions under which ending currents characterize geometrically finite actions, obtaining several equivalent conditions and some surprises, illustrated by an example of a geometrically infinite action whose ending currents are all supported on a single orbit of peripheral subgroups.
ER -