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Continuum theory, point-set topology, spaces with algebraic structure, foundations, dimension theory, local and global properties.

4 votes
1 answer
570 views

A question on Möbius strip and Jordan curve

If $A\subset \Bbb R^2$ then is the following statement true? $\{(x,y)\in {(A\times A)/ \sim}\,\,\,|\,\, (x,y)\sim(y,x)\}\simeq$ Möbius strip $\iff A$ is a Jordan curve.
C.F.G's user avatar
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2 votes
0 answers
132 views

Example of compact fiber bundle with noncompact fibers

This is a cross post of MSE post somehow: Is there any example of compact fiber bundle $E$ with noncompact fibers $F$? Obviously if the base space $B$ is $T_1$ then there is no such example.
C.F.G's user avatar
  • 4,195
3 votes
2 answers
408 views

A question on continuous maps from Möbius to itself

Let $M$ denotes the Möbius strip. Then is it true that For every continuous map $f:M\to M$ there is $x\in M^\circ$ ($x\notin\partial M$) such that $f(f(x))=x$?
C.F.G's user avatar
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0 votes
1 answer
532 views

Is the meaning of "irreducible manifold", "not reducible to other manifold"?

This is a cross post of MSE. Q1: What does "irreducible manifold" mean (not definition)? My understanding of "irreducible manifold" is "is not reducible (homotopic or deformation or homeomorph or be …
C.F.G's user avatar
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2 votes

Is the meaning of "irreducible manifold", "not reducible to other manifold"?

Summary of comments and other sources There are at least 4 similar concepts: Irreducible smooth manifold: As Ryan Budney said, "Regarding high dimensions, generally irreducible manifolds do not exist …
C.F.G's user avatar
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