Absolute geometry

Absolute geometry is a geometry that does not assume the parallel postulate or any of its alternatives. Its theorems are therefore true in non-Euclidean geometries, such as hyperbolic geometry and elliptic geometry, as well as in Euclidean geometry. In Euclid's Elements, the first 28 Propositions avoid using the parallel postulate, and therefore can be included in absolute geometry.

Absolute geometry is, in some places, referred to as neutral geometry, as it is neutral with respect to the parallel postulate.Template:Geometry-stub