(Topology Problem) Finding an interesting homeomorphism

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Homework Help Overview

The problem involves exploring the homeomorphism between the space NxNx[0,1) and the interval [0,1), specifically questioning the nature of their topological properties and whether such a homeomorphism exists.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to construct a homeomorphism by mapping [0, 1) to NxNx[0, 1) and discusses the challenges posed by the differing cardinalities of the sets involved. Some participants question the validity of the homeomorphism based on the connectedness of the sets, while others suggest reconsidering the implications of the dictionary order topology on NxNx[0,1).

Discussion Status

The discussion is ongoing, with participants expressing skepticism about the existence of a homeomorphism due to the topological properties of the sets. There is an exploration of different perspectives, particularly regarding the impact of the dictionary order topology on the argument.

Contextual Notes

Participants are considering the implications of connectedness and cardinality in the context of homeomorphisms, as well as the specific topology applied to NxNx[0,1). There is a noted lack of consensus on the initial assumptions regarding the homeomorphic relationship.

GridironCPJ
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Homework Statement


NxNx[0,1) is homeomorphic to [0, 1). Find an explicit homeomorphism.
(Note that N=naturals)


Homework Equations


A function f is a homeomorphism if:
(1) f is bijective
(2) f is continuous
(3) f inverse is continuous


The Attempt at a Solution


Finding a map from [0, 1) to NxNx[0, 1) seems easier. So, we would have a function of the following structure:

F([0, 1))=(g([0,1)), g([0, 1)), h([0, 1))) s.t. g([0, 1))=N and h([0, 1))=[0, 1), so clearly h is just the identity function, which is clearly bijective. Now, the question is how to get a function g that is bijective. [0, 1) is uncountable and N is countably infinite, so the cardinalities do not correspond. Perhaps my idea will not work. Let me know what you all think and feel free to express any other ideas.
 
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I don't believe for a second that \mathbb{N}\times \mathbb{N}\times [0,1) is homeomorphic to [0,1).
 
For one thing, [0, 1) is a connected set. NxNx[0, 1) is not connected.
 
Whoops, I forgot to mentione that NxNx[0,1) has the dictionary order topology. Does this change your mind?
 

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