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Timeline for Deformations of a blowup

Current License: CC BY-SA 3.0

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Feb 20, 2015 at 23:43 history edited Francesco Polizzi CC BY-SA 3.0
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Feb 20, 2015 at 21:54 history edited Francesco Polizzi CC BY-SA 3.0
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Feb 20, 2015 at 21:42 comment added jmc Thanks, I think that is clearer. (But now you also have $k_{s}$ in the long exact sequence, where it actually should be $k$, right?) Anyway, I do get your answer, and it very clear. Thanks for your effort!
Feb 20, 2015 at 21:40 history edited Francesco Polizzi CC BY-SA 3.0
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Feb 20, 2015 at 21:38 comment added Francesco Polizzi I edited the answer writing $k_s \oplus k_s$ instead of $k \oplus k$.
Feb 20, 2015 at 20:08 vote accept jmc
Feb 20, 2015 at 20:08 comment added jmc Sorry for my ignorance. I confused the notation $k \oplus k$ with the constant sheaf; but I guess it was implicit that you meant the skyscraper sheaf.
Feb 20, 2015 at 18:23 comment added Francesco Polizzi Right, it is a skyscraper sheaf supported on $s$. The exact sequence I wrote follows by applying $\beta_*$ to the exact sequence $$0 \to T_X \to \beta^* T_S \to \mathcal{O}_E(1) \to 0.$$
Feb 20, 2015 at 16:50 history edited Francesco Polizzi CC BY-SA 3.0
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Feb 20, 2015 at 16:47 comment added jmc Awesome, thanks! Seems I need to get hold of another book by Hartshorne (-; I don't get the short exact sequence though. The first two sheaves are isomorphic outside $s$, right? So the $k \oplus k$ should be a skyscraper supported on $s$, right? Or am I messing up in a stupid way?
Feb 20, 2015 at 16:38 history answered Francesco Polizzi CC BY-SA 3.0