We had a paper reading seminar on Vafa-Witten invariants of surfaces and necessary backgrounds. 

Organizational: Tuesday 3:00 - 4:30 at APM 5829

List of lectures: 

• Oct. 29. Bochao Kong. Virtual fundamental class.

• Nov. 5. Shubham Sinha. Examples of virtual fundamental classes in enumerative geometry.

• Nov. 12. Woonam Lim. Vafa-Witten invariants of surfaces.

• Nov. 19. Woonam Lim. Continuation of the last lecture.

• Nov. 26. Michail Savvas. K-theoretic refined Vafa-Witten invariants.

• Dec. 3. Michail Savvas. Continuation of the last lecture. 

List of references in order: 

• [Behrend, Fantechi] The intrinsic normal cone.

• [Siebert] Virtual fundamental classes, global normal cones and Fulton's canonical classes.

• [Tanaka, Thomas] Vafa-Witten invariants for projective surfaces I: stable case.

• [Thomas] A K-theoretic Fulton class.

• [Thomas] Equivariant K-theory and refined Vafa-Witten invariants.