Möbius transformations and the Poincaré distance in the quaternionic setting

dc.creatorBisi, Cinzia
dc.creatorGentili, Graziano
dc.date2008-05-03
dc.date2008-06-01
dc.date.accessioned2026-07-07T09:41:48Z
dc.date.available2026-07-07T09:41:48Z
dc.descriptionIn the space $\hh$ of quaternions, we investigate the natural, invariant geometry of the open, unit disc $Δ_{\hh}$ and of the open half-space $\hh^{+}$. These two domains are diffeomorphic via a Cayley-type transformation. We first study the geometrical structure of the groups of Möbius transformations of $Δ_{\hh}$ and $\hh^{+}$ and identify original ways of representing them in terms of two (isomorphic) groups of matrices with quaternionic entries. We then define the cross-ratio of four quaternions, prove that, when real, it is invariant under the action of the Möbius transformations, and use it to define the analogous of the Poincaré distances on $Δ_{\hh}$ and $\hh^{+}$. We easily deduce that there exists no isometry between the quaternionic Poincaré distance of $Δ_{\hh}$ and the Kobayashi distance inherited by $Δ_{\hh}$ as a domain of $\mathbb{C}^{2}$, in accordance with a direct consequence of the classification of the non compact, rank 1, symmetric spaces.
dc.descriptionDetails added in proof of Theorem 6.4. Exposition improved in some ambiguous points. References added. 28 pages
dc.identifierhttps://arxiv.org/abs/0805.0357
dc.identifierhttp://arxiv.org/abs/0805.0357
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/161957
dc.subjectComplex Variables
dc.subject30G35, 30C20, 30F45
dc.titleMöbius transformations and the Poincaré distance in the quaternionic setting
dc.typetext

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