Greg Stevenson's user avatar
Greg Stevenson's user avatar
Greg Stevenson's user avatar
Greg Stevenson
  • Member for 14 years, 5 months
  • Last seen more than a week ago
79 votes
Accepted

How do I check if a functor has a (left/right) adjoint?

49 votes
Accepted

Order of an automorphism of a finite group

48 votes
Accepted

How do I know the derived category is NOT abelian?

28 votes
Accepted

What is the "right" definition of a ring?

26 votes

Pushouts in the Category of Schemes

25 votes
Accepted

What is the opposite category of the category of modules (or Hopf algebra representations)?

22 votes
Accepted

Why do people "forget" Verdier abelianization functor?(Looking for application)

21 votes
Accepted

triangulated vs. dg/A-infinity

20 votes
Accepted

Noetherian local ring and the growth of $\dim_k \operatorname{Ext}^i(k,k)$

18 votes
Accepted

Nonprojective Surface

18 votes
Accepted

Splitting in triangulated categories

16 votes
Accepted

What is the relationship between t-structure and Torsion pair?

14 votes

Why is it a good idea to study a ring by studying its modules?

14 votes
Accepted

Characterization of schemes whose dualizing complex is perfect

13 votes

When does sheaf cohomology commute with arbitrary direct sums?

13 votes

Some intuition behind the five lemma?

12 votes
Accepted

Intuitive Example of a Jacobson Radical

12 votes

Categories which are not compactly generated

11 votes
Accepted

Is the chain homotopy category, K(Ab), an Abelian category? By Ab, I mean the category of Abelian groups.

10 votes

Abelian category which is not well-powered

10 votes
Accepted

Classifying triangulated structures on a graded category

10 votes

What is an intuitive view of adjoints? (version 1: category theory)

10 votes

Presheaves as limits of representable functors?

9 votes
Accepted

Freyd-Mitchell for triangulated categories?

9 votes
Accepted

Does the fiber product of two normal varieties remain normal?

9 votes
Accepted

Verdier duality via Brown representability?

9 votes
Accepted

Matrix factorization categories beyond the isolated singularity case

8 votes
Accepted

Can one extend a morphism of commutative triangles to a morphism of octahedral diagrams?

8 votes
Accepted

Is the tensorproduct of a triangulated category with a ring again triangulated?

8 votes
Accepted

Graded local rings versus local rings