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6 votes
1 answer
565 views

Canonical comparison between $\infty$ and ordinary derived categories

This question is a follow-up to a previous question I asked. If $\mathcal{D}(\mathsf{A})$ is the derived $\infty$-category of an (ordinary) abelian category $\mathsf{A},$ then the homotopy category $h\...
Stahl's user avatar
  • 1,179
4 votes
1 answer
237 views

Gluing isomorphism in derived categories along filtered colimit

Let $X$ be a locally finite type algebraic stack $X$ (but feel free to pretend it's a scheme) with a presentation as the filtered colimit of finite type open substacks $U_i$. By descent, at the level ...
user333154's user avatar
21 votes
1 answer
750 views

The derived category does not satisfy descent - example

One motivation for studying infinity categories is that the derived category does not satisfy Zariski descent, although the infinity categorical version does. I would like to see an example of Zariski ...
Mathmop's user avatar
  • 313
2 votes
0 answers
309 views

Invariants of objects in $\operatorname{Ch}(\mathrm{Ab})$ up to chain homotopy

$\newcommand\Ab{\mathrm{Ab}}\newcommand\ab{\mathrm{ab}}\DeclareMathOperator\Ch{Ch}\DeclareMathOperator\Kom{Kom}\newcommand\ho{\mathrm{ho}}$Let $\Ab$ be the category of finitely generated abelian ...
Student's user avatar
  • 5,038
6 votes
2 answers
893 views

Projective objects in the derived category of chain complexes

I have been trying to understand projective objects in the derived category of chain complexes of modules over a ring. If we stick to the category of chain complexes, the only projective objects are ...
Sofía Marlasca Aparicio's user avatar
2 votes
0 answers
78 views

Derived category of a exact categories with (unusual) weak equivalences

Every exact category $\mathcal{E}$ has an attached derived category (for simplicity I will just refer to the bounded one) $D^b(\mathcal{E})$. The construction is for example explained in A. Neeman, ...
JeeheBo5's user avatar
8 votes
2 answers
767 views

Derived functors out of an unbounded derived $\infty$-category

Let $\mathcal A$ be an abelian category. In this lecture, Thomas Nikolaus Defines the unbounded derived category $\mathcal D(\mathcal A)$ as $\mathcal K(\mathcal A)[W^{-1}]$, where $\mathcal K(\...
Tomo's user avatar
  • 1,187
1 vote
0 answers
193 views

Computing the cotangent complex of morphisms of perfect complexes

In Lurie's Spectral Algebraic Geometry the cotangent complex of $\textbf{Perf}$ is computed as $ \Sigma^{-1}( \mathscr{F} \otimes \mathscr{F}^\vee)$ for some universal $\mathscr{F} \in \text{Qcoh}(\...
Anette's user avatar
  • 595
8 votes
1 answer
1k views

Derived category of abelian sheaves on a site equivalent to sheaves on the derived category of abelian groups

Reading Scholze's notes on Condensed Mathematics it is mentioned that when considered as $\infty$-categories, $$ D(\operatorname{Cond(Ab)}) \cong \operatorname{Cond}(D(\operatorname{Ab}))$$ and that ...
Sofía Marlasca Aparicio's user avatar
9 votes
1 answer
1k views

Functorial kernel in derived category

By the work of Verdier, we know that cones in a triangulated category $\mathcal{T}$ are functorial if and only if $\mathcal{T}$ is semisimple abelian. However, in these notes, it is said that In the ...
curious math guy's user avatar
1 vote
2 answers
665 views

On the link between homology and homotopy

In the last semester I learned homological algebra and higher category theory/homotopy theory. But I am kind of confused when I try to really understand the link between the two subjects (this is ...
Amos Kaminski's user avatar
11 votes
2 answers
1k views

The relation between t-structures and derived category

Let $\mathcal{D}$ be a triangulated category and a $t$-structure $(\mathcal{D}^{\leq 0},\mathcal{D}^{\geq 0})$ on $\mathcal{D}$. The heart of the $t$-structure, $\mathcal{A}=\mathcal{D}^{\leq 0} \cap ...
Amos Kaminski's user avatar
1 vote
1 answer
144 views

Morphisms on fibre products

Let $X$ and $Y$ be two quasi compact, separated schemes over $k$, and consider the fibre product $X \times Y$. If we call $p_1$ and $p_2$ the two projections, and we take perfect complexes $F_1, F_2 \...
Federico Barbacovi's user avatar
1 vote
1 answer
381 views

Is the pushforward of a closed immersion of spectral Deligne-Mumford stacks conservative?

Let $ X \hookrightarrow Y$ be a closed immersion of (connective) spectral Deligne-Mumford stacks, is $ i_* : Qcoh(X) \rightarrow Qcoh(Y)$ conservative? Somehow I couldn't find the statement in SAG...
Anette's user avatar
  • 595
10 votes
1 answer
847 views

$\infty$-categorical understanding of Bridgeland stability?

On triangulated categories we have a notion of Bridgeland stability conditions. Is there any known notion of "derived stability conditions" on a stable $\infty$-category $C$ such that they become ...
dumb's user avatar
  • 103

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