orthonormal frames
21Cartan connection — In the mathematical field of differential geometry, a Cartan connection is a flexible generalization of the notion of an affine connection. It may also be regarded as a specialization of the general concept of a principal connection, in which the …
22Mathematics of general relativity — For a generally accessible and less technical introduction to the topic, see Introduction to mathematics of general relativity. General relativity Introduction Mathematical formulation Resources …
23Classifying space for U(n) — In mathematics, the classifying space for the unitary group U(n) is a space B(U(n)) together with a universal bundle E(U(n)) such that any hermitian bundle on a paracompact space X is the pull back of E by a map X → B unique up to homotopy. This… …
24G-structure — In differential geometry, a G structure on an n manifold M , for a given structure group [Which is a Lie group G o GL(n,mathbf{R}) mapping to the general linear group GL(n,mathbf{R}). This is often but not always a Lie subgroup; for instance, for …
25Normal coordinates — In differential geometry, normal coordinates at a point p in a differentiable manifold equipped with a symmetric affine connection are a local coordinate system in a neighborhood of p obtained by applying the exponential map to the tangent space… …
26Differential 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:… …
27Stress (mechanics) — Continuum mechanics …
28Rotation (mathematics) — Rotation of an object in two dimensions around a point O. In geometry and linear algebra, a rotation is a transformation in a plane or in space that describes the motion of a rigid body around a fixed point. A rotation is different from a… …
29Monochromatic electromagnetic plane wave — In general relativity, the monochromatic electromagnetic plane wave spacetime is the analog of the monochromatic plane waves known from Maxwell s theory. The precise definition of the solution is a bit complicated, but very instructive. Any exact …
30Observer (special relativity) — The term observer in special relativity refers most commonly to an inertial reference frame. Less often it may refer to an arbitrary non inertial reference frame; in particular, a Rindler frame is sometimes called an accelerating observer . In… …
