The refinement and reverse of a geometric inequality.
The Regge symmetry is a scissors congruence in hyperbolic space.
The residually weakly primitive geometries of .
The return sequence of the Bowen-Series map for punctured surfaces
For a non-compact hyperbolic surface M of finite area, we study a certain Poincaré section for the geodesic flow. The canonical, non-invertible factor of the first return map to this section is shown to be pointwise dual ergodic with return sequence (aₙ) given by aₙ = π/(4(Area(M) + 2π)) · n/(log n). We use this result to deduce that the section map itself is rationally ergodic, and that the geodesic flow associated to M is ergodic with respect to the Liouville measure. ...
The role of Sommerville tetrahedra in numerical mathematics
In this paper we summarize three recent results in computational geometry, that were motivated by applications in mathematical modelling of fluids. The cornerstone of all three results is the genuine construction developed by D. Sommerville already in 1923. We show Sommerville tetrahedra can be effectively used as an underlying mesh with additional properties and also can help us prove a result on boundary-fitted meshes. Finally we demonstrate the universality of the Sommerville's construction by...
The Rotation Group
We introduce length-preserving linear transformations of Euclidean topological spaces. We also introduce rotation which preserves orientation (proper rotation) and reverses orientation (improper rotation). We show that every rotation that preserves orientation can be represented as a composition of base proper rotations. And finally, we show that every rotation that reverses orientation can be represented as a composition of proper rotations and one improper rotation.
The second extension of the Thas-Walker construction.
The Skew-Hyperbolic Motion Group of the Quaternion Plane.
The smallest arithmetic hyperbolic three-orbi-fold.
The Steiner Ratio Conjecture for Cocircular Points.
The Tangent cone of an Aleksandrov space of curvature.
The theorem of desargues in planes with analogues to Euclidian angular bisectors.
The theorems of Stewart and Steiner in the Poincaré disc model of hyperbolic geometry
In [Comput. Math. Appl. 41 (2001), 135--147], A. A. Ungar employs the Möbius gyrovector spaces for the introduction of the hyperbolic trigonometry. This Ungar's work plays a major role in translating some theorems from Euclidean geometry to corresponding theorems in hyperbolic geometry. In this paper we explore the theorems of Stewart and Steiner in the Poincaré disc model of hyperbolic geometry.
The theorems of Urquhart and Steiner-Lehmus in the Poincaré ball model of hyperbolic geometry
The Translation Planes of Order 16 that Admit Nonsolvable Collineation Groups.
The tree of life and other affine buildings.
The triangular extensions of a generalized quadrangle of order .
The Two Most Algebraic K3 Surfaces.
The uniqueness of groups of type J4.
The universal embedding of the near polygon .