# Interface to Hyperbolic Models¶

This module provides a convenient interface for interacting with models of hyperbolic space as well as their points, geodesics, and isometries.

The primary point of this module is to allow the code that implements hyperbolic space to be sufficiently decoupled while still providing a convenient user experience.

The interfaces are by default given abbreviated names. For example, UHP (upper half plane model), PD (Poincaré disk model), KM (Klein disk model), and HM (hyperboloid model).

Note

All of the current models of 2 dimensional hyperbolic space use the upper half plane model for their computations. This can lead to some problems, such as long coordinate strings for symbolic points. For example, the vector (1, 0, sqrt(2)) defines a point in the hyperboloid model. Performing mapping this point to the upper half plane and performing computations there may return with vector whose components are unsimplified strings have several sqrt(2)’s. Presently, this drawback is outweighted by the rapidity with which new models can be implemented.

AUTHORS:

• Greg Laun (2013): Initial version.
• Rania Amer, Jean-Philippe Burelle, Bill Goldman, Zach Groton, Jeremy Lent, Leila Vaden, Derrick Wigglesworth (2011): many of the methods spread across the files.

EXAMPLES:

sage: HyperbolicPlane().UHP().get_point(2 + I)
Point in UHP I + 2

sage: HyperbolicPlane().PD().get_point(1/2 + I/2)
Point in PD 1/2*I + 1/2

class sage.geometry.hyperbolic_space.hyperbolic_interface.HyperbolicModels(base)

The category of hyperbolic models of hyperbolic space.

class ParentMethods
super_categories()

The super categories of self.

EXAMPLES:

sage: from sage.geometry.hyperbolic_space.hyperbolic_interface import HyperbolicModels
sage: H = HyperbolicPlane()
sage: models = HyperbolicModels(H)
sage: models.super_categories()
[Category of metric spaces,
Category of realizations of Hyperbolic plane]

class sage.geometry.hyperbolic_space.hyperbolic_interface.HyperbolicPlane

The hyperbolic plane $$\mathbb{H}^2$$.

Here are the models currently implemented:

• UHP – upper half plane
• PD – Poincaré disk
• KM – Klein disk
• HM – hyperboloid model
HM
Hyperboloid
KM
KleinDisk
PD
PoincareDisk
UHP
UpperHalfPlane
a_realization()

Return a realization of self.

EXAMPLES:

sage: H = HyperbolicPlane()
sage: H.a_realization()
Hyperbolic plane in the Upper Half Plane Model

sage.geometry.hyperbolic_space.hyperbolic_interface.HyperbolicSpace(n)

Return n dimensional hyperbolic space.

EXAMPLES:

sage: from sage.geometry.hyperbolic_space.hyperbolic_interface import HyperbolicSpace
sage: HyperbolicSpace(2)
Hyperbolic plane