Skip to main content
10 events
when toggle format what by license comment
Apr 13, 2017 at 12:58 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Jan 9, 2013 at 11:17 history edited Michael Zieve CC BY-SA 3.0
deleted 567 characters in body; added 246 characters in body
Jan 7, 2013 at 10:38 comment added aglearner Sorry in the last comment I meant that degree four curves in $\mathbb CP^2$ form a Zariski OPEN (not only dense) subset in $M_3$.
Jan 7, 2013 at 8:46 comment added aglearner Michael, I don't see how you would use in your reasoning the fact that genus $g$ curve is generic. If you remove this assumption, it is very easy to construct a counterexample to that fact that you have assumed. Namely, the space of genus $3$ curves that admit a morphism to an elliptic curve is Zariski dense (in the moduli space $M_3$ of all genus $3$ curves), but it is by no means open. Since degree four curves in $\mathbb CP^3$ from a Zariski dense subset of $M_3$ we see a contradiction.
Jan 7, 2013 at 7:13 comment added Michael Zieve Really? Then I take it back. I thought it would be straightforward to get that, if there were a morphism from a smooth plane curve of degree $d$ to a generic genus-$g$ curve, then there is a family of morphisms from a Zariski-open subset of degree-$d$ plane curves to genus-$g$ curves. If that's not true, then I was wrong.
Jan 7, 2013 at 6:47 comment added Serge Lvovski @Michael: In principle it is possible that each curve og genus $g$ can be covered by a plane curve, but these mappings do not "glue" into a dominant rational mapping from the space of plane curves of a given degree onto $M_g$.
Jan 7, 2013 at 4:22 comment added aglearner After some thinking I don't see any (non-superficial) relation between the question you cite and my question, so I would like to ask you give details on how you want to deform $C'$ with its morphism.
Jan 6, 2013 at 23:45 comment added aglearner Dear Zieve I would like to know why you can deform $C'$ in the way you descibe. I don't see this.
Jan 6, 2013 at 23:33 history edited Michael Zieve CC BY-SA 3.0
added 375 characters in body; added 51 characters in body
Jan 6, 2013 at 23:05 history answered Michael Zieve CC BY-SA 3.0