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Hyperbolic geometry
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(Redirected from Lobachevskian geometry)
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)