Dan Petersen
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Registered User
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Ph.D. student in algebraic geometry.
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6h |
revised |
What does “Vertex Solution” mean? edited tags |
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May 17 |
accepted | Generalization of the Lefschetz fixed point theorem |
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May 16 |
revised |
Generalization of the Lefschetz fixed point theorem added 81 characters in body |
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May 16 |
answered | Generalization of the Lefschetz fixed point theorem |
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May 15 |
revised |
Magic trick based on deep mathematics added 12 characters in body |
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May 14 |
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Internal Day convolution I don't think that's a reason not to accept it. For instance, I think a lot of people will happily upvote a question that they only partially understand, but will hesitate to do the same with an answer (because in this case the upvote could be seen as a "certificate" of correctness). |
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May 9 |
awarded | ● Good Answer |
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May 9 |
revised |
Can we have A={A} ? added 6 characters in body |
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May 6 |
revised |
Frobenius weights on etale cohomology and purity edited body |
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May 6 |
accepted | Frobenius weights on etale cohomology and purity |
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May 6 |
answered | Frobenius weights on etale cohomology and purity |
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May 4 |
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Analogue of Knudsen clutching This question makes no sense as stated. Precisely what moduli stacks of pointed varieties are you considering? |
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May 2 |
revised |
Does anyone know where I can get a copy of Gaunce Lewis’s thesis? added 4 characters in body |
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May 1 |
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Dense Affine Subvarieties of Algebraic Varieties You can trivially reduce to the case when the connected components of $X$ are irreducible: just shrink $X$ to a smaller variety $X'$ by throwing out all points lying on more than one irreducible component. Then $X'$ is open and dense in $X$ and it suffices to find a dense affine in $X'$. |
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Apr 30 |
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Does every simplicial polytope have a topology-preserving contractible edge? "On a $d$-simplex, no edge is contractible. [...] Does every simplicial polytope have a contractible edge?". I think you just answered your own question. |
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Apr 28 |
accepted | Thom-Gysin Sequences and Stratifications |
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Apr 28 |
answered | Thom-Gysin Sequences and Stratifications |
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Apr 26 |
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Is the moduli space of ppAVs smooth? J. Martel, either I am misunderstanding you or you are confused. The locus of Jacobians is not closed in $A_g$ for any $g \geq 2$, its closure is the locus of products of Jacobians. When $g=2$ every ppav is a Jacobian or a product of two elliptic curves. |
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Apr 25 |
accepted | Is the moduli space of ppAVs smooth? |
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Apr 25 |
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Is the moduli space of ppAVs smooth? I agree with all of this but it seems tough going to refer to Faltings--Chai for this result. The OP seems content to work over the complex numbers and then smoothness of the moduli stack amounts to saying that there exists a finite index subgroup of $\mathrm{Sp}(2g,\mathbf Z)$ which acts freely on Siegel space. |
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Apr 25 |
answered | Is the moduli space of ppAVs smooth? |
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Apr 24 |
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A_infinity structure on cohomology and the weight filtration The last paragraph doesn't sound right to me - shouldn't the $m_n$ be compatible with weights on the nose? |
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Apr 24 |
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A_infinity structure on cohomology and the weight filtration A relevant question is: mathoverflow.net/questions/22064/… |
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Apr 20 |
accepted | smooth modular compactification of moduli of curves |
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Apr 17 |
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Contractibility of a configuration space In what sense is it a manifold? |
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Apr 16 |
revised |
smooth modular compactification of moduli of curves deleted 67 characters in body |
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Apr 16 |
answered | smooth modular compactification of moduli of curves |
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Apr 15 |
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Cohomology of configuration spaces @Nicholas Proudfoot: On the other hand, all Christin asked for was a procedure for computing the Betti numbers, not a closed formula. I know Orsola Tommasi wrote a computer program computing the Betti numbers of Totaro's DGA for an elliptic curve, you could e-mail her and ask for the code. |
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Apr 14 |
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Cohomology of configuration spaces @Geoffroy: the paper you reference deals with configuration spaces of unordered points, not ordered... |
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Apr 14 |
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Cohomology of configuration spaces Sorry, but why doesn't Totaro's paper answer your question? |
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Apr 11 |
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Are period domains ever contractible dhagbert: see mathoverflow.net/questions/67699 ... |
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Apr 10 |
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Minimal compactification Actually $A_g$ is a hermitian symmetric space, so the minimal compactification doesn't just mimic the construction of Satake-Baily-Borel: it is a special case of it. |
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Apr 3 |
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How should one understand orbifold fundamental groups? Oh, I understand now. Thanks! |
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Apr 3 |
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How should one understand orbifold fundamental groups? I think in your last paragraph you mean "...with a cover $U_i$ possessing A subordinate partition of unity..." |
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Mar 30 |
awarded | ● Necromancer |
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Mar 27 |
answered | Prorepresentable functors repres. by alg. spaces? Covering spaces by alg. spaces. |
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Mar 25 |
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Have you seen this one parameter family of distributions before? Please don't ask identical questions here and on math.SE, it leads to duplication of effort. math.stackexchange.com/questions/340205/… |
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Mar 20 |
accepted | $f,f',…,f^{(j)}$ is $\mathbb C$-linearly independent if $f$ is a modular form |
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Mar 20 |
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Representability of sheaves of groups See also mathoverflow.net/questions/8918 for a related question. |
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Mar 19 |
answered | $f,f',…,f^{(j)}$ is $\mathbb C$-linearly independent if $f$ is a modular form |
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Mar 18 |
accepted | Alexander duality theorem |
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Mar 17 |
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Alexander duality theorem In my proof it is a closed, not necessarily compact, oriented submanifold (e.g. a line in the plane). Is it incorrect? |
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Mar 17 |
revised |
Alexander duality theorem added 119 characters in body |
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Mar 17 |
answered | Alexander duality theorem |
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Mar 13 |
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What can we say about this generalization of simply-connectedness? Could it be that the correct generalization is that a product of a $d$-simple and a $d'$-simple variety is $(d+d')$-simple? |
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Mar 13 |
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What can we say about this generalization of simply-connectedness? @Will Sawin: I don't even know what it means for the stack $M_1$ to be affine! Note that we can not consider the usual DM-stack of elliptic curves $M_{1,1}$, since we are explicitly not assuming the existence of a section. |
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Mar 13 |
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A Universal Elliptic Curve deleted 88 characters in body |
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Mar 13 |
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What can we say about this generalization of simply-connectedness? ulrich: does your argument really work for $g = 1$? The universal cover of $M_g$ is Teichmüller space only for $g \geq 2$. |
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Mar 13 |
answered | A Universal Elliptic Curve |
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Mar 2 |
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Is the operadic butterfly symmetric? Shouldn't such a functor also interchange Zinb and Leib? |
