Peng Zhou

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blog:2024-12-04 [2024/12/05 09:33] – [Twisted Sheaves] pzhoublog:2024-12-04 [2024/12/05 09:51] (current) – [Twisted Sheaves] pzhou
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 How to take a sheaf of categories and take the global section? Or given a diagram of categories, how to take the limit? Suppose we are trying to get $Coh(\P^1)$ twisted by a complex number $c$ How to take a sheaf of categories and take the global section? Or given a diagram of categories, how to take the limit? Suppose we are trying to get $Coh(\P^1)$ twisted by a complex number $c$
 $$ Coh(\P^1 \RM \infty ) \xto{res \otimes O(c)} Coh(\C^*) \gets Coh(\P^1 \RM 0) $$ $$ Coh(\P^1 \RM \infty ) \xto{res \otimes O(c)} Coh(\C^*) \gets Coh(\P^1 \RM 0) $$
 +Now, what is $O(c)$ on $\C^*$? I want to say it is a holomorphic line bundle that does not have any global section (so probably shouldn't be called a coherent sheaf), it is constructed by considering $\C^* \cong \C / \Z$, we consider line bundle given by the quotient $(\C \times \C) / \Z$, where the $\Z$ action is 
 +$$(z, \eta) \mapsto (z+ 2\pi i , \eta e^{c z})$$
 +Indeed, we have $e^z = y$ (hmm, if $c=1$, I am supposed to still get a trivial bundle)
 +
 +OK, maybe we use analytic topology on $\C^*$.
  
blog/2024-12-04.1733391212.txt.gz · Last modified: 2024/12/05 09:33 by pzhou