Hitchin Fibrations and P=W
Fall 2026
Fall 2026
The goal of this reading seminar is to understand the statement and proof of the P=W conjecture: we will use the third proof given in the paper of Maulik-Shen-Yin. We will also spend some time understanding the paper of Hausel-Thaddeus.
We will meet on Mondays from 1:00PM to 2:30PM at MIT 2-255, for a 75 min talk followed by a 15 minute discussion session. The 15 minutes is for overflow time, so you should plan your talk to be an hour and expect questions.
A tentative schedule for the reading seminar can be found here. The schedule for the talks for week 7-11 are subject to change, depending on audience interests. Possible topics include: Arinkin's paper and MSY in the full support compactified Jacobian case, de Cataldo-Maulik-Shen (tautological classes are in correct perversity), Ngo support theorems and Springer theory.
If you have any questions or would like to join the mailing list, please email the organizers Yonghwan Kim (yonghkim@mit.edu) and Anne Larsen (annelars@mit.edu).
Suggested references
Arinkin - Autoduality of compactified Jacobians for curves with plane singularities
Beauville - Sur la cohomologie de certains espaces de modules de fibres vectoriels
de Cataldo, Maulik, Shen - Hitchin fibrations, abelian surfaces, and the P=W conjecture
de Cataldo, Migliorini - The decomposition theorem, perverse sheaves, and the topology of algebraic maps
Hausel, Thaddeus - Mirror symmetry, Langlands duality, and the Hitchin system
Hoskins - Two proofs of the P=W conjecture
Markman - Generators of the cohomology ring of moduli spaces of sheaves on symplectic surfaces
Maulik, Shen, Yin - Perverse filtrations and Fourier transforms
Mellit - Cell decompositions of character varieties
Shende - The weights of the tautological classes of character varieties
Schedule
Week 1 (Sep 21) Overview (Leonid) Notes
Week 2 (Sep 28) Spectral curves and Hitchin fibers (Kaiyi) Notes
Week 3 (Oct 5) Duality, Gerbes, and Mirror symmetry (Yonghwan) Notes
Columbus day
Week 4 (Oct 19) Weight filtrations and mixed Hodge structures (Merrick)
Week 5 (Oct 26) Perverse sheaves and perverse filtration (Yutong)
Week 6 (Nov 2) Tautological classes generate (Dylan)
Week 7 (Nov 9) Overview of the Maulik-Shen-Yin proof (Anne)
Week 8 (Nov 16)
Thanksgiving
Week 9 (Nov 30) Arinkin's paper (Xinchun)
Week 10 (Dec 7)
Week 11 (Dec 14)