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Difference between revisions of "Dominant of a topological space"

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''<img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338201.png" />''
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$X$
  
Any topological space for which <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338202.png" /> serves as a retract (cf. [[Retract of a topological space|Retract of a topological space]]).
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Any topological space for which $X$ serves as a retract (cf. [[Retract of a topological space]]).
  
  
  
 
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====Comments====
This is not standard Western terminology; there is in fact no name for this concept. The standard Western usage of dominating is as follows: A space <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338203.png" /> is said to dominate a space <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338204.png" /> if and only if there are continuous mappings <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338205.png" /> and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338206.png" /> such that <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338207.png" /> is homotopic to the identity mapping (on <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d033/d033820/d0338208.png" />).
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This is not standard Western terminology; there is in fact no name for this concept. The standard Western usage of dominating is as follows: A space $X$ is said to dominate a space $Y$ if and only if there are continuous mappings $f : X \rightarrow Y$ and $g : Y \rightarrow X$ such that $fg$ is homotopic to the identity mapping (on $Y$).
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Latest revision as of 17:20, 29 September 2016

$X$

Any topological space for which $X$ serves as a retract (cf. Retract of a topological space).


Comments

This is not standard Western terminology; there is in fact no name for this concept. The standard Western usage of dominating is as follows: A space $X$ is said to dominate a space $Y$ if and only if there are continuous mappings $f : X \rightarrow Y$ and $g : Y \rightarrow X$ such that $fg$ is homotopic to the identity mapping (on $Y$).

How to Cite This Entry:
Dominant of a topological space. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Dominant_of_a_topological_space&oldid=39348
This article was adapted from an original article by A.V. Chernavskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article