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Paul Fabel's user avatar
Paul Fabel's user avatar
Paul Fabel
  • Member for 13 years, 4 months
  • Last seen this week
  • Mississippi State University
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What are some natural examples of "bimorphism" classes?
Mentioning another popular example of a category with lots of bimorphisms but few isomorphisms
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What is your favorite proof of Tychonoff's Theorem?
The mentioned pretty simple direct proof also uses Zorn's Lemma.
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Are the higher homotopy groups of the Hawaiian earring trivial?
The paper of Cannon/Conner/Zastrow correctly proves planar compacta are aspherical. My answer/comments below sketches an alternate, strategy/technique to achieve the same result via different methods. I expect the gaps can be filled in, but the purported alternate proof has yet to be written up carefully and published.
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Is “factoring through a dendrite loop” preserved under deletion?
Yes. In fact the Hilbert cube will suffice as a target, the topological countable product of closed intervals. The difficulties of the original question manifest themselves when the image of a loop is not 1 dimensional, for example if we assume all loops under consideration have image in 3 dimensional Euclidean space.
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Topological characterization of injective metric spaces
Is there a reasonable conjecture as to a plausible answer? ( For example the question at hand reminds me of the following: Are the topological spaces which underly length spaces precisely the metrizable, connected and locally path connected spaces?)
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