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163 questions with no upvoted or accepted answers
24 votes
0 answers
709 views

What is the status of a result of Kontsevich and Rosenberg?

In their influential paper Noncommutative Smooth Spaces (https://arxiv.org/abs/math/9812158), Kontsevich and Rosenberg define the notion of a noncommutative projective space. In Section 3.3 they ...
Adam Nyman's user avatar
15 votes
0 answers
627 views

Full Exceptional Collection of Vector Bundles for Toric Varieties

Kawamata showed the derived category of coherent sheaves on a smooth projective toric variety has a full exceptional collection consisting of sheaves. I was wondering if it is know whether every ...
Juliette Bruce's user avatar
13 votes
0 answers
715 views

Why do people study unbounded derived category of quasi-coherent sheaves rather than focus on bounded derived category of coherent sheaves?

Let $X$ be a scheme and let $D_{qoch}(X)$ and $D^b_{coh}(X)$ be the unbounded derived category of quasi-coherent sheaves and bounded derived category of coherent sheaves on $X$, respectively. $D^b_{...
Zhaoting Wei's user avatar
  • 8,767
12 votes
0 answers
314 views

Comparing derived categories of quasi-coherent sheaves in the lisse-etale and the big etale toplogy on an algebraic stack

I am trying to understand the proof of Proposition 1.4.2. in "A study of derived algebraic geometry Volume 1" by Gaitsgory-Rozenblyum. http://www.math.harvard.edu/~gaitsgde/GL/QCohBook.pdf, page 8. ...
Anette's user avatar
  • 595
11 votes
0 answers
443 views

K-stability is invariant under D-equivalency

Kawamata conjectured that Let $X$ and $Y$ be birationally equivalent smooth projective varieties. Then the following are equivalent. We denote by $D^b(Coh(X))$ the derived category of bounded ...
user avatar
10 votes
0 answers
183 views

Derived equivalences preserved by blow-ups

Let $X$ and $Y$ be smooth projective varieties over $\mathbb{C}$. Assume that $X$ and $Y$ are derived equivalent. Let $\pi : \tilde{X} \longrightarrow X$ be a blow-up of $X$ along a smooth center. Can ...
Libli's user avatar
  • 7,250
10 votes
0 answers
525 views

What is the mirror of an algebraic group?

Background: Kontsevich's homological mirror symmetry conjecture posits the existence of pairs $(X,\check X)$ with an equivalence of dg/$A_\infty$-categories $$\mathcal F(X)=\mathcal D^b(\check X)$$ ...
John Pardon's user avatar
  • 18.5k
10 votes
0 answers
428 views

McKay correspondence and tensor products

The theorem of Bridgeland-King-Reid says that if $M$ is a smooth quasi-projective complex variety of dimension at most $3$ on which a finite group $G$ acts such that the canonical sheaf $\omega_M$ is $...
Benjamin Antieau's user avatar
9 votes
0 answers
501 views

Categorification of definitions in the context of the derived category of quasi-coherent sheaves

Let $SpecA=X$ be an affine noetherian scheme. Let $QCoh(X)$ denote the derived (stable $\infty$-)category of quasi-coherent sheaves on $X$. There are the following special full subcategories spanned ...
Saal Hardali's user avatar
  • 7,689
9 votes
0 answers
329 views

Is the perfectness of Fourier-Mukai kernels proved by Toen?

In Toen's paper The homotopy theory of dg-algebras and derived Morita theory, Theorem 8.15, he essentially proved the following result. Let $X$ and $Y$ be two smooth and proper schemes over $k$. ...
Zhaoting Wei's user avatar
  • 8,767
8 votes
0 answers
331 views

Beilinson's theorem for fixed stratifications

Beilinson's theorem states that for a variety $X$ and a field $k$ the realization functor $$\text{real}: D^b\text{Perv}(X,k)\to D_c^b(X,k)$$ is an equivalence of categories. If we only consider ...
Sergey Guminov's user avatar
8 votes
0 answers
260 views

Direct summands of a pushforward in the derived category of coherent sheaves

For a Noetherian scheme $X$, let $D^b(X)$ denote the bounded derived category of coherent sheaves on $X$. Let $X$ be a Noetherian scheme, $i:Y \hookrightarrow X$ a closed subscheme and $F$ an object ...
naf's user avatar
  • 10.5k
8 votes
0 answers
143 views

Equivariant coherent sheaf category for unipotent group actions

Suppose $U$ is a complex algebraic unipotent group. Let $X$ be a projective variety with a $U$-action. For simplicity, we may assume that there are only finite many $U$ orbits on $X$. The primary ...
Amanda Taylor's user avatar
7 votes
0 answers
315 views

Bondal-Orlov' theorem for noncommutative projective schemes

My question is very simple. Is Bondal-Orlov's theorem known for noncommutative projective schemes in the sense of Artin and Zhang? The commutative version is the following : Let $X, Y$ be smooth ...
Walterfield's user avatar
7 votes
0 answers
292 views

Derived symmetric powers and determinants

Given a vector bundle $V$ (on a scheme $X$, say), I can form $Sym(V[1])$, the symmetric algebra (in the derived/graded sense) on the shift of $V$; in other words this is the Koszul complex of the zero ...
Tom Bachmann's user avatar
  • 1,951

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