- #1
Fernsanz
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Hi.
I'm trying to understand why is the Zorn's lemma needed to prove the Tychonoff theorem -the product of compact spaces is compact-.
Specifically my question is about the proof in the book from Bachman-Narici based on the technic of Finite Intersection Property that you can find here:
http://books.google.es/books?id=wCH...resnum=1&ved=0CBcQ6AEwAA#v=onepage&q&f=false"
Why can not we just carry over the proof of the finite case? I mean, once the point [tex]\hat{x}[/tex] has been proposed as the common adherence point and bearing in mind the basis for the topology of [tex]X[/tex] consists of the sets
[tex]\prod V_{\alpha}[/tex] where [tex]V_{\alpha}[/tex] is an open set [tex]V_{\alpha} \subset X_{\alpha}[/tex] for finitely many [tex]\alpha[/tex] and [tex]X_{\alpha}[/tex] for the rest, it is obvious that any of these basis set containing [tex]\hat{x}[/tex] will also intersect all of [tex]E^{\gamma}[/tex]. So, where and why is the Zorn's lemma needed?
Thanks in advance.
I'm trying to understand why is the Zorn's lemma needed to prove the Tychonoff theorem -the product of compact spaces is compact-.
Specifically my question is about the proof in the book from Bachman-Narici based on the technic of Finite Intersection Property that you can find here:
http://books.google.es/books?id=wCH...resnum=1&ved=0CBcQ6AEwAA#v=onepage&q&f=false"
Why can not we just carry over the proof of the finite case? I mean, once the point [tex]\hat{x}[/tex] has been proposed as the common adherence point and bearing in mind the basis for the topology of [tex]X[/tex] consists of the sets
[tex]\prod V_{\alpha}[/tex] where [tex]V_{\alpha}[/tex] is an open set [tex]V_{\alpha} \subset X_{\alpha}[/tex] for finitely many [tex]\alpha[/tex] and [tex]X_{\alpha}[/tex] for the rest, it is obvious that any of these basis set containing [tex]\hat{x}[/tex] will also intersect all of [tex]E^{\gamma}[/tex]. So, where and why is the Zorn's lemma needed?
Thanks in advance.
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