antipodal mapping
1Duality (projective geometry) — A striking feature of projective planes is the symmetry of the roles played by points and lines in the definitions and theorems, and (plane) duality is the formalization of this metamathematical concept. There are two approaches to the subject of …
2Stereographic projection — In geometry, the stereographic projection is a particular mapping (function) that projects a sphere onto a plane. The projection is defined on the entire sphere, except at one point mdash; the projection point. Where it is defined, the mapping is …
3Charts on SO(3) — In mathematics, the special orthogonal group in three dimensions, otherwise known as the rotation group SO(3), is a naturally occurring example of a manifold. The various charts on SO(3) set up rival coordinate systems: in this case there cannot… …
4Roman surface — The Roman surface (so called because Jakob Steiner was in Rome when he thought of it) is a self intersecting mapping of the real projective plane into three dimensional space, with an unusually high degree of symmetry. The mapping is not an… …
5Differential geometry of surfaces — Carl Friedrich Gauss in 1828 In mathematics, the differential geometry of surfaces deals with smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives:… …
6Hairy ball theorem — The hairy ball theorem of algebraic topology states that there is no nonvanishing continuous tangent vector field on the sphere. If f is a continuous function that assigns a vector in R3 to every point p on a sphere such that f ( p ) is always… …
7Lambert azimuthal equal-area projection — The Lambert azimuthal equal area projection is a particular mapping from a sphere to a disk. It accurately represents area in all regions of the sphere, but it does not accurately represent angles. Intuitively, it gives a planar picture of the… …
8Mercury (planet) — Mercury  ☿ …
9Geographic coordinate system — Map of Earth showing lines of latitude (horizontally) and longitude (vertically), Eckert VI projection; large version (pdf, 3.12MB) …
10Non-Euclidean geometry — Behavior of lines with a common perpendicular in each of the three types of geometry Non Euclidean geometry is the term used to refer to two specific geometries which are, loosely speaking, obtained by negating the Euclidean parallel postulate,… …
