bio | website | math.berkeley.edu/~achinger |
---|---|---|
location | Berkeley | |
age | 28 | |
visits | member for | 5 years, 2 months |
seen | 5 hours ago | |
stats | profile views | 3,209 |
PhD student, UC Berkeley
Apr 11 |
reviewed | Approve Intuition for Integral Transforms |
Apr 11 |
comment |
Interpreting Frobenius pullback as an invariant differential in the case of an elliptic curve
Is $S$ affine? / Shouldn't $H^1(E, \mathcal{O}_E)$ be $R^1 f_* \mathcal{O}_E$? If $E=S$, we should have ${\rm Lie}(E/S)=0$... |
Mar 26 |
awarded | Self-Learner |
Mar 21 |
comment |
Is the ring $\mathbb{Z}_p [[x]]\otimes_{\mathbb{Z}_p} \overline{\mathbb{Q}}_p$ Noetherian?
Brilliant! Thank you. |
Mar 21 |
accepted | Is the ring $\mathbb{Z}_p [[x]]\otimes_{\mathbb{Z}_p} \overline{\mathbb{Q}}_p$ Noetherian? |
Mar 17 |
revised |
Is the ring $\mathbb{Z}_p [[x]]\otimes_{\mathbb{Z}_p} \overline{\mathbb{Q}}_p$ Noetherian?
added 5 characters in body; edited title |
Mar 17 |
asked | Is the ring $\mathbb{Z}_p [[x]]\otimes_{\mathbb{Z}_p} \overline{\mathbb{Q}}_p$ Noetherian? |
Mar 13 |
comment |
Covering of schemes and flatness
The normalization of a cuspidal curve is a bijective finite map which is not flat. |
Feb 19 |
comment |
Artin approximation of a diagram
What do you mean by approximate? Whether there exists a $\phi'$ in some etale neighborhoods inducing $\phi$ upon completion? Then the answer is no as we can take $Z$ to be a point, $(X, x)=(\mathbb{A}^1, 0)$, $(Y, y) = (\mathbb{A}^1, 1)$ and $\phi = \exp$. Or approximate up to order $N$ for any given $N$? Then I think the answer is yes, because we can apply approximation to the graph of $\phi$. |
Feb 9 |
comment |
Definition and sigularity of Ramified covers
In general the cyclic cover will be ramified everywhere on $D$, so if $D\cap {\rm Sing}(X)$ is big there is no hope. |
Feb 9 |
comment |
Definition and sigularity of Ramified covers
Be careful, because the cyclic covers as defined need not be normal if $D$ is non-reduced: in the simple example $X=\mathbb{A}^1$, $D=2\cdot (x)$ the recipe gives the non-normal $\tilde X = {\rm Spec}(k[x,y]/(x^2-y^3)$. But it's easy to compute the normalization, which is ${\rm Spec_X} \bigoplus_{i=0}^{n-1} \mathcal{O}_X(\lfloor \frac{i}{n}D \rfloor)$. |
Feb 6 |
awarded | Yearling |
Feb 2 |
awarded | Popular Question |
Feb 1 |
comment |
Reference request: log Fano varieties
What if $X$ is not projective? |
Jan 29 |
awarded | Popular Question |
Jan 13 |
comment |
Intersections of $B$ and $B^-$ orbits in the flag variety $G/B$
It is also stated there that their closures are Cohen-Macaulay, so in particular they are equi-dimensional. |
Jan 13 |
comment |
Intersections of $B$ and $B^-$ orbits in the flag variety $G/B$
I think they are called (open) Richardson varieties. Their dimensions are described here: arxiv.org/pdf/1008.3939v2.pdf (page 2). |
Jan 12 |
awarded | Guru |
Jan 8 |
comment |
Is there a “simplification” functor in algebraic topology?
Universal in the homotopy category, I presume? |
Jan 8 |
awarded | Taxonomist |