Seminar on Stacks (Oberseminar)

Termin: Monday 16-18 Uhr in WSC-N-U-4.04
Dozenten J. Heinloth

We will usually start the seminar with a discussion/Q&A/recap-session on one of the Thursday seminars.
Afterwards we discuss a topic/an article one of us wants to understand, the choice for the next topic is usually made at the end of the seminar. This term we will start with a series on BPS-cohomology.

The list below will thus be updated regularly, a list of links to articles and preprints discussed is included below.

Date	Speaker	Titel
17.4.2026	Jochen Heinloth	Introduction
20.4.2026	Jochen Heinloth	Discussion (2502.04253 start of Section 7)
27.4.2026	Davood Nejaty	Perverse sheaves, purity and the decomposition theorem
4.5.2026	reserved	PhD talks & interviews
11.5.2026	Veronica Licchelli	Kinjo’s decomposition theorem for gms maps
18.5.2026	Yingying Wang	Proposition 7.2.1 and Corollary 7.2.4
25.5.2026	N.N.
1.6.2026	N.N.
8.6.2026	N.N.
15.6.2026	N.N.
22.6.2026	N.N.
29.6.2026	N.N.
6.7.2026	N.N.
13.7.2026	N.N.	reserved
20.7.2025	N.N.

Links to Articles and Preprints for the different topics:

Notes on stacks and moduli (by Jarod Alper)
BPS cohomology in geometry and representation theory (by Ben Davison)
Cohomology of symmetric stacks (by Chenjing Bu, Ben Davison, Andrés Ibánez Núunez, Tasuki Kinjo, Tudor Padurariu)
Cohomological Donaldson–Thomas theory of a quiver with potential and quantum enveloping algebras (by Ben Davison and Sven Meinhardt)
Decomposition theorem for good moduli morphisms by Tasuki Kinjo