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network profile
| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 2 months |
| seen | Feb 7 at 18:18 | |
| stats | profile views | 252 |
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Mar 16 |
awarded | Yearling |
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Feb 3 |
asked | What are the easiest surfaces of general type |
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Feb 3 |
comment |
An example of decomposing a projective variety Have you tried showing your variety is irreducible? You could use the "dictionary" between closed subsets of projective $n$-space and ideals of k[a_0,\ldots,a_n]$. Being irreducible as a closed subset usually boils down to the polynomials being irreducible. |
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Feb 3 |
suggested | suggested edit on Definition of tamely ramified |
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Feb 2 |
comment |
Is the number of automorphisms of a hyperelliptic curve bounded The curve $y^2=x^{2g+1}+1$ admits the automorphism $(x,y)\mapsto (\zeta_{2g+1}^n x, y)$ for all $n=1,\ldots,2g+1$. Thus, the number of automorphisms of this hyperelliptic curve is at least $2g+1$. Is this correct? |
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Jan 31 |
asked | Is the number of automorphisms of a hyperelliptic curve bounded |
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Jan 31 |
accepted | Elliptic curves over Spec Z |
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Jan 30 |
revised |
Elliptic curves over Spec Z added 77 characters in body |
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Jan 30 |
asked | What do we know about smooth families over the open unit disc |
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Jan 29 |
comment |
Elliptic curves over Spec Z I wanted to be sure myself, but let $E$ be an elliptic curve over $\mathbf Q$ with good reduction over $\mathbf Z$. Then its minimal regular model coincides with its minimal Weierstrass model. |
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Jan 29 |
asked | Elliptic curves over Spec Z |
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Jan 25 |
revised |
Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) added 63 characters in body |
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Jan 25 |
accepted | Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) |
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Jan 25 |
revised |
Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) deleted 134 characters in body |
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Jan 25 |
comment |
Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) Yes, I just wanted to be sure. Thank you for this. It completely cleared up everything. |
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Jan 25 |
comment |
Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) I think I understand what I'm doing wrong now. Starting with $Y\to X$ as in the question, the base change gives $Y\times_X X^\prime \to X^\prime$. This is not necessarily etale, but once you normalize you obtain $Y^\prime\to X^\prime$ and this morphism is etale by Abhyankar. Now, if by some chance $Y^\prime = Y\times_X X^\prime$ (i.e., the base change is normal) then faithfully flat descent implies that the morphism we started out with was already etale. Thank you very much QiL!! |
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Jan 25 |
comment |
Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) By "some maximal ideal" do you mean "any maximal ideal", or does Abhyankar really mean that there is maybe just "one" maximal ideal? |
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Jan 24 |
asked | Is there a construction known for associating a K3 surface to a curve or cover of curves |
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Jan 24 |
asked | Doesn't Abhyankar's lemma contradict faithful flat descent (no, but I'm confused) |
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Jan 24 |
accepted | Is a group with only finitely many subgroups of index n (for all n) finitely generated |
