Skip to main content
6 events
when toggle format what by license comment
Feb 11, 2022 at 11:39 comment added user505117 Does this answer imply, by choosing $\bigoplus \mathcal{O}_{\mathbb{P}}(a_i)=0$, that on $\mathbb{P}^1$ we have $\tau^* \mathcal{O}(2) \simeq \mathcal{O}(2)$, where $\tau$ is complex conjugation? That doesn't seem right, because $d \tau$ defines an isomorphism $T \mathbb{P}^1 = \overline{T \mathbb{P}^1}=(T \mathbb{P}^1)^*$, i.e. an isomorphism from $\mathcal{O}(2)$ to $\mathcal{O}(-2)$. Also, $\tau$ does not preserve $c_1(\mathcal{O}(2))$.
Aug 17, 2010 at 8:27 comment added Francesco Polizzi F. Catanese wrote some papers on this subject. For instance "Moduli spaces of surfaces and real structures", Ann. Math. 158. But I do not remember whether he considers also the case of coherent sheaves. One can find all of them on arXiv.
Aug 17, 2010 at 1:01 comment added Donu Arapura I wish I could recommend a reference, but I'm not sure of one. Perhaps someone else can help?
Aug 17, 2010 at 0:45 comment added Dmitry Kerner Thanks for the reply. Of course I meant X is stabilized by $\tau$. (It implies that X is defined over the reals, right?) If a presentation is given one can define the complex conjugation. But the conjugation can be defined in various ways. Apparently they are all compatible, but probably this should be proved? Could you recommend some short intro/summary?
Aug 17, 2010 at 0:31 history edited Donu Arapura CC BY-SA 2.5
added 5 characters in body
Aug 17, 2010 at 0:18 history answered Donu Arapura CC BY-SA 2.5