Closed unit interval: Difference between revisions

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{{particular topospace}}
==Definition==
==Definition==


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| <math>[a,a+1]</math> for <math>a \in \R</math> || equivalent as a metric space; in fact, equivalent as a subset of the metric space <math>\R</math>, in the sense that an isometry of <math>\R</math> (translation) sends <math>[0,1]</math> to <math>[a,a + 1]</math>
| <math>[a,a+1]</math> for <math>a \in \R</math> || equivalent as a metric space; in fact, equivalent as a subset of the metric space <math>\R</math>, in the sense that an isometry of <math>\R</math> (translation) sends <math>[0,1]</math> to <math>[a,a + 1]</math>
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| <math>[a,b]</math> for <math>a,b \in \R</math>, <math>a < b</math> || equivalent as a (differential) ormanifold with boundary and hence also as a topological space. Conformally equivalent as a metric space or as a Riemannian manifold with boundary.
| <math>[a,b]</math> for <math>a,b \in \R</math>, <math>a < b</math> || equivalent as a (differential) manifold with boundary and hence also as a topological space. Conformally equivalent as a metric space or as a Riemannian manifold with boundary.
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| Two-point compatification of real line, with points introduced at <math>-\infty</math> and <math>+\infty</math> || equivalent as a (differential) manifold with boundary and hence also as a topological space.
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| Any compact 1-manifold with boundary || equivalent as a (differential) manifold with boundary.
| Any compact 1-manifold with boundary || equivalent as a (differential) manifold with boundary.

Revision as of 00:01, 10 October 2010

This article is about a particular topological space (uniquely determined up to homeomorphism)|View a complete list of particular topological spaces

Definition

As a subset of the real numbers

The closed unit interval is defined as the interval [0,1] or the set {xR0x1}.

As a metric space

The closed unit interval is the metric space [0,1] with the Euclidean metric.

As a manifold with boundary

Fill this in later

As a topological space

The closed unit interval is the set [0,1] with the subspace topology induced from the real line.

Equivalent spaces

Space How strongly is it equivalent to the closed unit interval?
[a,a+1] for aR equivalent as a metric space; in fact, equivalent as a subset of the metric space R, in the sense that an isometry of R (translation) sends [0,1] to [a,a+1]
[a,b] for a,bR, a<b equivalent as a (differential) manifold with boundary and hence also as a topological space. Conformally equivalent as a metric space or as a Riemannian manifold with boundary.
Two-point compatification of real line, with points introduced at and + equivalent as a (differential) manifold with boundary and hence also as a topological space.
Any compact 1-manifold with boundary equivalent as a (differential) manifold with boundary.
Any contractible space homotopy-equivalent