Symplectic Field Theory and the Symplectic Cobordism Category

General Information:

Place: 1.023 (BMS Seminar room) Johann von Neumann Haus, Rudower Chaussee 25, 12489 Berlin

Time: Mondays 13:15-14:45 (October 2026-February 2027)

Credits: 5 LP for local students

Moodle: If you plan to participate in the seminar, please join the moodle (the enrollment key is "hierarchy"). The moodle will be used for occasional time-sensitive announcements. Users affiliated with the HU can access moodle using their HU username and password. Non-HU users can access it by following this link and then clicking on "Create new account".

Overview: This is a working group seminar run by Chris Wendl, Thomas Walpuski and Klaus Mohnke. This semester (WiSe 2026-27), the seminar has a general theme: (R)SFT and the symplectic cobordism category.

The symplectic cobordism category has objects as contact manifolds of dimension 2n-1, and morphisms as symplectic cobordisms between them of dimension 2n. Symplectic cobordisms are much more rigid objects compared to smooth cobordisms, and have many interesting properties. For example, symplectic cobordisms are not symmetric and induce some kind of a partial order on the space of contact manifolds While we know somewhat about them in dimension 4, a lot is unknown in higher dimensions.

The goal is to understand some recent results and advances in the topic, more specifically to understand the work of Moreno-Zhou; the series of two papers: 

• A landscape of contact manifolds via rational SFT (Moreno-Zhou I)

• RSFT functors for strong cobordisms and applications (Moreno-Zhou II)

Along the way, we will also go through some basic ideas in SFT as well as works of Wendl, Latschev-Wendl, Avdek-Zhou, Zhou, etc.

If you would like to participate and / or prepare for a talk, but are not sure about your background, please feel free to write an email to: apratim.choudhury@hu-berlin.de . We can then set up a meeting and discuss further.

Seminar Plan: A rough plan of the seminar is described below, with links to papers and references. The first day of the seminar will be used to plan and distribute the talks among willing participants.

• 19.10.26 : General introduction and planning for the semester - 

• 26.10.26 :  A review of the (R)SFT algebra package: Weyl, BV_{\infty},... - 

• 02.11.26 :  Algebraic torsion in contact manifolds (Latschev-Wendl) - 

• 09.11.26 :  Non-exact symplectic cobordisms between contact 3 manifolds (Wendl) - 

• 16.11.26 : L_{\infty} and BL_{\infty} algebras (Moreno-Zhou I) - 

• 03.11.26 : Rational symplectic field theory as a BL_{\infty} algebra (Moreno-Zhou I) - 

• 30.11.26 : Implementation of virtual techniques (Moreno-Zhou I) - 

• 07.12.26 : Review talk? - 

• 14.12.26 : Bounds on planarity  (Moreno-Zhou I) - 

• 04.01.27 : Applications of the hierarchy functor (Moreno-Zhou I) - 

• 11.01.27 : RSFT functors for strong cobordisms I (Moreno-Zhou II) - 

• 18.01.27 : RSFT functors for strong cobordisms II (Moreno-Zhou II) - 

• 25.01.27 : Bourgeois contact manifolds are tight (Avdek-Zhou) - 

• 01.02.27 : Algebraic planar torsion in contact manifolds (Zhou) - 

• 08.02.27 :