Homeomorphism of Unit Circle and XxX Product Space

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SUMMARY

The discussion concludes that there is no topological space X such that the product space X x X is homeomorphic to the unit circle in the plane. The reasoning is based on the properties of open sets and path-connectedness. Specifically, if such a homeomorphism existed, an open set U in X would need to be path-connected, leading to a contradiction when considering U x U minus a point compared to the real line minus a point, which is not path-connected. Additionally, examining the fundamental groups reinforces this conclusion.

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Is there atopological space X such that XxX (the product space) is homeomorphic to the unit circle in the plane
 
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No. If there were such a homeomorphism, then there would be an open set U in X such that U x U is homeomorphic to an open arc in the 1-sphere. In other words U x U is homeomorphic to the real line. It should be simple enough to see that U is path-connected and an easy argument shows that U x U minus a point is still path-connected. On the other hand the real line minus a point is not path-connected. Contradiction.
 
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You could also look at the fundamental groups.
 

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