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[parent] cone (Definition)

Given a topological space $X$ the cone on $X$ (sometimes denoted by $CX$ is the quotient space $X\cross [0,1]/X\cross\set{0}.$ Note that there is a natural inclusion $X\hookrightarrow CX$ which sends $x$ to $(x,1).$ If $(X,x_0)$ is a based topological space, there is a similar reduced cone construction, given by $X\cross [0,1] / (X\cross\set{0})\cup(\set{x_0}\cross[0,1]).$ With this definition, the natural inclusion $x\mapsto (x,1)$ becomes a based map, where we take $(x_0,0)$ to be the basepoint of the reduced cone.




"cone" is owned by antonio.
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See Also: suspension, join

Also defines:  reduced cone

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Cross-references: basepoint, map, similar, based topological space, inclusion, quotient space, topological space
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This is version 4 of cone, born on 2003-02-05, modified 2004-11-22.
Object id is 3974, canonical name is Cone.
Accessed 5901 times total.

Classification:
AMS MSC54B99 (General topology :: Basic constructions :: Miscellaneous)

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