We show that plane hyperbolic geometry, expressed in terms of points and the ternary relation of collinearity alone, cannot be expressed by means of axioms of complexity at most ∀∃∀, but that there is an axiom system, all of whose axioms are ∀∃∀∃ sentences. This remains true for Klingenberg's genera
The Hyperbolic Derivative in the Poincaré Ball Model of Hyperbolic Geometry
✍ Scribed by Graciela S. Birman; Abraham A. Ungar
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 115 KB
- Volume
- 254
- Category
- Article
- ISSN
- 0022-247X
No coin nor oath required. For personal study only.
✦ Synopsis
The generic Mobius transformation of the complex open unit disc induces a binary operation in the disc, called the Mobius addition. Following its introduction, ẗhe extension of the Mobius addition to the ball of any real inner product space änd the scalar multiplication that it admits are presented, as well as the resulting geodesics of the Poincare ball model of hyperbolic geometry. The Mobius gyrovec-´ẗor spaces that emerge provide the setting for the Poincare ball model of hyper-bolic geometry in the same way that vector spaces provide the setting for Euclidean geometry. Our summary of the presentation of the Mobius ball gyrovector spaces sets the stage for the goal of this article, which is the introduction of the hyperbolic derivative. Subsequently, the hyperbolic derivative and its application to geodesics uncover novel analogies that hyperbolic geometry shares with Euclidean geometry.
📜 SIMILAR VOLUMES
## Abstract Let \documentclass{article}\usepackage{amssymb,amsmath,amsthm,amscd,amsxtra}\begin{document}\pagestyle{empty}$\mathbb {H}^n$\end{document} be the __n__‐dimensional hyperbolic space. It is well‐known that, if \documentclass{article}\usepackage{amssymb,amsmath,amsthm,amscd,amsxtra}\begin{