Timeline for Intersections with divisors on moduli of curves

8 events

when toggle format	what		by	license	comment
May 11, 2012 at 18:31	history	edited	OldMacdonaldHadaForm	CC BY-SA 3.0	deleted 2 characters in body
May 11, 2012 at 18:30	comment	added	OldMacdonaldHadaForm		Dear Jason Starr, thank you very much for your comment. I will rephrase the question to include only the case $k=1$, which is the one I was originarily interested in.
May 11, 2012 at 18:00	comment	added	Jason Starr		Dear OMHF: Yes, there are choices of $\gamma$ such that $\gamma^k$ is zero. For instance, at least for many choices of $(g,n)$, there are nonconstant morphisms $u:\overline{M}_{g,n}\to Y$ with positive fiber dimension. If $\gamma$ is the pullback under $u$ of any divisor class from $Y$, then $\gamma^k$ will be zero for $k> \text{dim}(Y)$.
May 11, 2012 at 17:43	comment	added	Felipe Voloch		Much better. The software running this site randomly bumps old unanswered questions from time to time. When it does so, it does under the name "MathOverflow", hence my request.
May 11, 2012 at 16:33	comment	added	OldMacdonaldHadaForm		Do you like this one better?
May 11, 2012 at 15:34	comment	added	Felipe Voloch		Pleasechange your username
May 11, 2012 at 14:45	history	edited	OldMacdonaldHadaForm	CC BY-SA 3.0	added 5 characters in body; added 13 characters in body
May 11, 2012 at 14:40	history	asked	OldMacdonaldHadaForm	CC BY-SA 3.0