The functor of continuous functions from compact CW-spaces to the reals - MathOverflow most recent 30 from http://mathoverflow.net2013-06-19T12:08:06Zhttp://mathoverflow.net/feeds/question/43974http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/43974/the-functor-of-continuous-functions-from-compact-cw-spaces-to-the-realsThe functor of continuous functions from compact CW-spaces to the realsroger1232010-10-28T14:01:56Z2010-10-28T15:55:13Z
<p>The contravariant functor $C(-)$ given by
$$
\hom_{Top}(-,\mathbb{R}):cCW\to Rng
$$
where $cCW$ is the category of compact CW complexes is injective on objects. What is known about surjectivity, faithfulness and fullness of this functor?</p>
http://mathoverflow.net/questions/43974/the-functor-of-continuous-functions-from-compact-cw-spaces-to-the-reals/43989#43989Answer by Dmitri Pavlov for The functor of continuous functions from compact CW-spaces to the realsDmitri Pavlov2010-10-28T15:53:01Z2010-10-28T15:53:01Z<p>Corollary 4.1.(i) in Johnstone's book Stone Spaces (electronic version: <a href="http://gen.lib.rus.ec/get?nametype=orig&md5=C26F62F69C32101307213F1960F85BA3" rel="nofollow">http://gen.lib.rus.ec/get?nametype=orig&md5=C26F62F69C32101307213F1960F85BA3</a>)
states that the category of realcompact spaces is dual to the full subcategory
of the category of commutative rings consisting of rings of the form C(X).
The functor C implements the duality.</p>
<p>The category of compact CW-complexes embeds into the category of realcompact
spaces as a full subcategory, hence the functor C is fully faithful.</p>