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David Treumann's user avatar
David Treumann's user avatar
David Treumann
  • Member for 15 years, 2 months
  • Last seen more than 6 years ago
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Hypercube decomposition of perverse sheaves
I added some references. If I now understand what Verdier specialization is, then by definition it differs from microlocalization just by a Fourier transform. I think the local system I am talking about will be present in the Fourier transforms of both the Verdier specialization and its vanishing part, possibly after shrinking our open set: if these two things differ by a relatively constant sheaf, then their Fourier transforms differ by something supported on the zero section.
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What functor does a Schubert variety represent?
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When are there enough projective sheaves on a space X?
To give a sheaf on your example is equivalent to giving abelian groups A1 A2 and A3 and maps A3 --> A1 and A3 --> A2. (The group Ai is the stalk of the sheaf at i.) The constant sheaf Z is itself projective in your example, but the sheaf you call Z_{\ge 1} is not: the surjection from the constant sheaf to this does not split
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When are there enough projective sheaves on a space X?
In the first sentence of your proof you use assume that X is locally connected--is that necessary? I was just about to edit my answer to hedge a little more and say that I don't know what's going on with the Cantor set.
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What are the possible images of a square under an area-preserving map?
This answer is more helpful and embarrassing for me, but I think it means that Anton is dead right.
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