This site is supported by donations to The OEIS Foundation.
Hyperbolic geometry
From OeisWiki
Hyperbolic geometry (a non-Euclidean geometry) is also called Lobachevskian geometry or Bolyai-Lobachevskian geometry.
Hyperbolic geometry has the properties
- negative curvature;
- the parallel postulate is false (in two dimensions, there are at least two distinct lines through a point not on line which do not intersect );
- the sum of angles of a triangle is less than 180 degrees.
See also
- Hyperbolic geometry (Lobachevskian geometry, with negative curvature)
- Parabolic geometry (Euclidean geometry, with null curvature)
- Elliptic geometry (Riemannian geometry, with positive curvature)