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3 votes
0 answers
99 views

Relation of geometric and polyhedral convergence

By Proposition 3.10(i) of Jorgensen and Marden's 1990 Algebraic and geometric convergence of Kleinian groups, "[A] sequence $\{G_n\}$ of Kleinian groups converges geometrically to a Kleinian ...
bergfalk's user avatar
4 votes
1 answer
230 views

Generalizing a result about hyperbolic 2-folds to hyperbolic 3-folds

$\DeclareMathOperator\SL{SL}\DeclareMathOperator\SO{SO}\DeclareMathOperator\SU{SU}$Let $ \Sigma_g $ be a compact orientable surface of genus $ g $. Let the subgroup $ \pi_1(\Sigma) $ of $ \SL_2(\...
Ian Gershon Teixeira's user avatar
2 votes
1 answer
719 views

Classification of isometries of hyperbolic 3-space

Denote the upper half space by $\mathcal{H}_{3}=\Bbb{C}\times (0,\infty)$. A point $P \in \mathcal{H}_{3}$ is given as, $P=(z, t)=(x, y, t)=z+t j$ where $z=x+i y$ and $j=(0,0,1) .$ The group $P S L_{2}...
ersin's user avatar
  • 33
2 votes
0 answers
127 views

Homeomorphism type of the horofunction boundary for nilpotent Lie groups

Consider a metric space $(X,d)$ and fix a base point $w$. A horofunction is a function of the form $$\beta_y(x)=d(x,y)-d(w,y).$$ The map $y\mapsto \beta_y$ is an embedding of $X$ into the space of $1$-...
M. Dus's user avatar
  • 2,090
16 votes
2 answers
756 views

Can a sphere glued into a soft 3d-mattress rotate continuously? (manifolds, SU(2) and the belt trick)

The question is triggered by the wonderful animations by Jason Hise: https://www.youtube.com/watch?v=LLw3BaliDUQ https://www.youtube.com/watch?v=6Ul_-ABYaYU https://www.youtube.com/watch?v=...
Messages from various people's user avatar
1 vote
1 answer
214 views

Orbits of Product Lie Groups Action

Hi to all, Let $G$ be a Lie group of linear isometries of $\mathbb{R}^n_{\nu}$ ($\mathbb{R}^n_{\nu}$ is the semi-Euclidean space) and $G_1$ ,$G_2$ two Lie subgroups of $G$. Let $G_1 \times G_2$ as ...
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