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Apr
28 |
comment |
local description of $\mathbb{P}^2$-fibrations over $\mathbb{P}^1$
@Sasha Nice reference, but only the case where the degenerating surface has quotient singularity is treated. Is there a way in general to have some kind of "canonical" birational map to a P^2 bundle? Or at least to something with mild singularities? (when I mean canonical, I mean something that would be equivariant why any group action). |
Apr
23 |
answered | Irreducible variety |
Feb
28 |
answered | Étale coverings of cubics and gluings |
Feb
28 |
comment |
Étale coverings of cubics and gluings
Yes but the exchanges is not compatible with the morphism $\tilde{X}\to X$. |
Feb
12 |
answered | One-dimension Algebraic groups |
Feb
3 |
awarded | Popular Question |
Dec
19 |
accepted | Rational solutions of the Fermat equation $X^n+Y^n+Z^n=1$ |
Dec
15 |
awarded | Nice Question |
Dec
14 |
revised |
Rational solutions of the Fermat equation $X^n+Y^n+Z^n=1$
deleted 172 characters in body |
Dec
14 |
asked | Rational solutions of the Fermat equation $X^n+Y^n+Z^n=1$ |
Dec
6 |
comment |
Pushing-forward morphisms
Nice answer. Thank you. |
Dec
6 |
accepted | Pushing-forward morphisms |
Dec
4 |
awarded | Nice Question |
Dec
4 |
awarded | Inquisitive |
Dec
3 |
comment |
Pushing-forward morphisms
Thanks Jason, this is a nice answer +1! It seems that you did not even use anything like non-ramified, right? Unfortunately, I would like such kind of result where $Y$ is not normal (neither is $X$ or $Z$) and also I would also be happy to have something in characteristic $p$ (but maybe it is too much to ask). I would be happy with $f$ and $\psi$ proper (to avoid the counterexamples you gave), and I added the condition of being unramified to remove the case of a morphism $X\to Z$ from a smooth curve to a cusp (for example). But maybe it does not work? |
Dec
3 |
asked | Pushing-forward morphisms |
Nov
21 |
comment |
Existence of a continuous section
Thanks for the nice comment. I did not know about this result. Are there some examples where $Y=[0,1]$ ? |
Nov
21 |
asked | Existence of a continuous section |
Nov
16 |
reviewed | Approve Is there a name for this fast growing functions? |
Nov
16 |
reviewed | Approve Is a Laskerian ring coherent |