Homotopy extension property

Homotopy extension property

In mathematics, in the area of algebraic topology, the homotopy extension property indicates when a homotopy can be extended to another one, so that the original homotopy is simply the restriction of the extended homotopy.

Definition

Given A subset X , we say that the pair mathbf{mathit{(A,X) has the homotopy extension property with respect to mathbf{mathit{Y if the following holds:

Given any continuous f: X o Y, g: A o Y for which there is a homotopy G: A imes I o Y of mathbf{mathit{f and mathbf{mathit{g, we can extend this to a homotopy F: X imes I o Y of mathbf{mathit{f and some mathbf{mathit{g', where g' : X o Y and g'mid A = g.

Other

If mathbf{mathit{(A,X) has the homotopy extension property independent of mathbf{mathit{Y, then the simple inclusion map i: A o X is a cofibration.

In fact, if you consider any cofibration i: Y o Z, then we have that mathbf{mathit{Y is homeomorphic to its image under mathbf{mathit{i. This implies that any cofibration can be treated as an inclusion map, and therefore it can be treated as having the homotopy extension property.

ee also

* Homotopy lifting property

References

*


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Homotopy lifting property — In mathematics, in particular in homotopy theory within algebraic topology, the homotopy lifting property (also known as the right lifting property or the covering homotopy axiom) is a technical condition on a continuous function from a… …   Wikipedia

  • Homotopy — This article is about topology. For chemistry, see Homotopic groups. The two dashed paths shown above are homotopic relative to their endpoints. The animation represents one possible homotopy. In topology, two continuous functions from one… …   Wikipedia

  • Extension (mathematics) — In mathematics, the word extension has many uses. See:Analysis* Carathéodory s extension theorem * Continuous linear extension * M. Riesz extension theorem * Krein extension theorem * Hahn Banach theoremAlgebra* Abelian extension * Algebraic… …   Wikipedia

  • List of mathematics articles (H) — NOTOC H H cobordism H derivative H index H infinity methods in control theory H relation H space H theorem H tree Haag s theorem Haagerup property Haaland equation Haar measure Haar wavelet Haboush s theorem Hackenbush Hadamard code Hadamard… …   Wikipedia

  • Cofibration — In mathematics, in particular homotopy theory, a continuous mapping , where A and X are topological spaces, is a cofibration if it satisfies the homotopy extension property with respect to all spaces Y. The name is because the dual condition, the …   Wikipedia

  • HEP — or hep can mean: * Hep Records, a jazz record label in Scotland * Habitat Evaluation Procedures, a method used to document the quality and quantity of available habitat for selected wildlife species * Head end power, a method for providing… …   Wikipedia

  • Monodromy — In mathematics, monodromy is the study of how objects from mathematical analysis, algebraic topology and algebraic and differential geometry behave as they run round a singularity. As the name implies, the fundamental meaning of monodromy comes… …   Wikipedia

  • List of algebraic topology topics — This is a list of algebraic topology topics, by Wikipedia page. See also: topology glossary List of topology topics List of general topology topics List of geometric topology topics Publications in topology Topological property Contents 1… …   Wikipedia

  • List of general topology topics — This is a list of general topology topics, by Wikipedia page. Contents 1 Basic concepts 2 Limits 3 Topological properties 3.1 Compactness and countability …   Wikipedia

  • mathematics — /math euh mat iks/, n. 1. (used with a sing. v.) the systematic treatment of magnitude, relationships between figures and forms, and relations between quantities expressed symbolically. 2. (used with a sing. or pl. v.) mathematical procedures,… …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”