- Metric derivative
In mathematics, the metric derivative is a notion of derivative appropriate to parametrized paths in metric spaces. It generalizes the notion of "speed" or "absolute velocity" to spaces which have a notion of distance (i.e. metric spaces) but not direction (such as vector spaces).
Let (M,d) be a metric space. Let have a limit point at . Let be a path. Then the metric derivative of γ at t, denoted | γ' | (t), is defined by
if this limit exists.
Recall that ACp(I; X) is the space of curves γ : I → X such that
for some m in the Lp space Lp(I; R). For γ ∈ ACp(I; X), the metric derivative of γ exists for Lebesgue-almost all times in I, and the metric derivative is the smallest m ∈ Lp(I; R) such that the above inequality holds.
where is the Euclidean metric.
- Ambrosio, L., Gigli, N. & Savaré, G. (2005). Gradient Flows in Metric Spaces and in the Space of Probability Measures. ETH Zürich, Birkhäuser Verlag, Basel. ISBN 3-7643-2428-7.
Wikimedia Foundation. 2010.
См. также в других словарях:
Derivative (generalizations) — Derivative is a fundamental construction of differential calculus and admits many possible generalizations within the fields of mathematical analysis, combinatorics, algebra, and geometry. Derivatives in analysis In real, complex, and functional… … Wikipedia
Metric differential — In mathematical analysis, a metric differential is a generalization of a derivative for a Lipschitz continuous function defined on a Euclidean space and taking values in an arbitrary metric space. With this definition of a derivative, one can… … Wikipedia
Metric tensor — In the mathematical field of differential geometry, a metric tensor is a type of function defined on a manifold (such as a surface in space) which takes as input a pair of tangent vectors v and w and produces a real number (scalar) g(v,w) in a… … Wikipedia
Metric connection — In mathematics, a metric connection is a connection in a vector bundle E equipped with a metric for which the inner product of any two vectors will remain the same when those vectors are parallel transported along any curve. Other common… … Wikipedia
Metric Pixel Canvas — The Metric Pixel Canvas is a pixel based derivative of the ISO 216 standard developed by Dennis Pennekamp to unite pixel based raster graphics with vector graphics on a square root of two based metric canvas. Size Dimensions (pixels) Dimensions… … Wikipedia
Metric compatibility — This article is about the concept in Riemannian geometry. For the typographic concept, see Typeface#Font metrics. In mathematics, given a metric tensor gab, a covariant derivative is said to be compatible with the metric if the following… … Wikipedia
Covariant derivative — In mathematics, the covariant derivative is a way of specifying a derivative along tangent vectors of a manifold. Alternatively, the covariant derivative is a way of introducing and working with a connection on a manifold by means of a… … Wikipedia
Fréchet derivative — In mathematics, the Fréchet derivative is a derivative defined on Banach spaces. Named after Maurice Fréchet, it is commonly used to formalize the concept of the functional derivative used widely in mathematical analysis, especially functional… … Wikipedia
Generalizations of the derivative — The derivative is a fundamental construction of differential calculus and admits many possible generalizations within the fields of mathematical analysis, combinatorics, algebra, and geometry. Contents 1 Derivatives in analysis 1.1 Multivariable… … Wikipedia
Glossary of Riemannian and metric geometry — This is a glossary of some terms used in Riemannian geometry and metric geometry mdash; it doesn t cover the terminology of differential topology. The following articles may also be useful. These either contain specialised vocabulary or provide… … Wikipedia