Olivier Benoist
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Registered User
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Jun 8 |
comment |
Nisnevich covers of algebraic spaces A reference for what ayanta explains above is [Knutson, Algebraic spaces, Chapter 2, Theorem 6.4]. |
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May 23 |
revised |
Irreducible divisors containing an arbitrary closed set added 324 characters in body |
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May 12 |
comment |
Gauss mapping in finite characteristic MP's reference provides counter-examples that are smooth space curves. On the other hand, all smooth plane curves have generically one-to-one Gauss map, by [Hajime Kaji : On the Gauss maps of space curves in characteristic p, Corollary 4.5]. |
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Apr 12 |
accepted | Counter-example to faithfully flat descent |
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Apr 12 |
revised |
Counter-example to faithfully flat descent edited tags |
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Apr 12 |
answered | Counter-example to faithfully flat descent |
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Apr 3 |
comment |
Existence of smooth surfaces containing a curve @Francesco : if $C$ is not reduced, $I_C(d)$ is still generated by global sections when $d\gg 0$ (as $I_C$ is coherent). It follows that the corresponding linear system has (set-theoretical) base locus consisting of $C$ only. |
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Apr 3 |
comment |
Existence of smooth surfaces containing a curve @Francesco : I do not understand your argument. Where do you use the fact that $C$ is reduced ? |
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Mar 19 |
answered | Explicit equation of Dickson invariant / quasideterminant / special orthogonal group over the integers |
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Mar 9 |
revised |
Line bundles on a pointless curve added 129 characters in body |
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Mar 9 |
accepted | Line bundles on a pointless curve |
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Mar 9 |
revised |
Line bundles on a pointless curve added 1134 characters in body |
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Mar 8 |
awarded | ● Enlightened |
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Mar 8 |
answered | Line bundles on a pointless curve |
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Mar 8 |
awarded | ● Nice Answer |
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Mar 8 |
revised |
Kodaira dimension of symmetric products of curves added 5 characters in body |
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Mar 8 |
accepted | Kodaira dimension of symmetric products of curves |
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Mar 8 |
answered | Kodaira dimension of symmetric products of curves |
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Feb 20 |
comment |
Spectrum and scheme of the commutative group-algebra of an abelian group. The fact that $Spec(Burn(G))$ is connected if and only if $G$ is solvable is certainly a geometrical characterization of a group-theoretic property. |
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Feb 20 |
answered | Spectrum and scheme of the commutative group-algebra of an abelian group. |
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Feb 7 |
comment |
2-cycle of K3 surface In the third paragraph of www.math.ens.fr/~wittenberg/transcendental.pdf, you'll find an explicit example of a K3 surface over $\mathbb{Q}$, with an elliptic fibration, such that the rank generated by a section and components of fibers is $20$, that is the maximum in characteristic $0$. |
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Feb 2 |
comment |
singular divisors in a complete linear system @Thunder: You'll find many more examples in the book "Projective duality and homogeneous spaces". |
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Jan 18 |
revised |
Irreducible divisors containing an arbitrary closed set added 4 characters in body |
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Jan 18 |
accepted | Irreducible divisors containing an arbitrary closed set |
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Jan 17 |
revised |
Irreducible divisors containing an arbitrary closed set added 171 characters in body |
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Jan 17 |
revised |
Irreducible divisors containing an arbitrary closed set added 629 characters in body |
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Jan 17 |
answered | Irreducible divisors containing an arbitrary closed set |
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Jan 10 |
awarded | ● Enlightened |
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Jan 10 |
awarded | ● Nice Answer |
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Dec 28 |
awarded | ● Yearling |
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Dec 23 |
comment |
Is the moduli space of genus three smooth quartics affine? Beware that analogous results for smooth complete intersections do not hold in general. For instance, the moduli space of non-hyperelliptic genus $4$ curves, that is the moduli space of smooth complete intersections of degrees $(2,3)$ in $\mathbb{P}^4$ is not affine, beacuse it contains complete curves. |
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Dec 22 |
revised |
flatness criterion on normal bases added 1 characters in body; edited title |
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Dec 22 |
answered | flatness criterion on normal bases |
