The Yang-Mills Equations over Riemann Surfaces Reading group 2020.


This is a page of information about the reading group for the Atiyah and Bott paper "The Yang-Mills Equations over Riemann Surfaces".

The reading group grew out of the PhD reading groups run through the Heriot-Watt Mathematical Physics group which most of the participants were members of.

We will decide on a reasonable number of pages to read each week, probably content dependent but likely to be under 10.

The participants include: Calum Ross (me) UCC, Lukas Müller MPI Bonn, Lennart Schmidt NUS, Vincenzo Marotta Heriot-Watt, Grigorios Giotopoulos HW, Bruno Barton-Singer HW, Juan Carlos Morales Parra HW, Corina Keller University of Monpellier, Luuk Stehouwer MPI Bonn, and others to be added.

The page here, is for a course which covered some of the same details and may be a useful resource and source of further references.

Date Pages of [1] that we read Presenter Summary of what we discussed
22/10/20 N/A N/A We had a brief chat about how we would proceed with the reading group. It was a housekeeping session where we discussed how to proceed. We have decided to aim for 1 hour sessions, 12:00-13:00 UK time (BST this week and GMT in future weeks), with ~30 minutes for a presentation and ~30 minutes for a discussion. The plan is for the presenter to change each week though there is no obligation to volunteer. I (Calum) will send round a PDF of the paper so that we all have a copy where the page numbers match up.
29/10/20 Introduction: pg 524 to 528 (pg 3 to pg 7 of the PDF) Calum We discussed the introduction and tried to get a feel for the spaces that we will study in the paper. The notes that I presented are uploaded here.
5/11/20 Section 1: Morse Theory: pg 528 to 533 (pg 7 to 12 of the PDF) Bruno Bruno gave a nice introduction to Morse theory and we spent a bit of time trying to understand the case of critical surfaces. We touched on equivariant Morse theory but decided to come back to that next week.
12/11/20 Section 1: Morse Theory: pg 528 to 534 (pg 7 to 13 of the PDF) Bruno We started by discussing the completion principle for critical submanifolds before moving on to equivariant Morse theory. Bruno presented the two examples: The height function on a sphere with a U(1) action, and the "mod" height function on the sphere with a U(1) action.
19/11/20 Section 13: Equivariant cohomology: pg 604 to 606 (pg 83 to 85 of the PDF) Lukas Lukas gave an intrduction to equivaraint cohomology following chapter 12 of [1]. The notes that he covered are uploaded here.
26/11/20 Section 1: Equivariant Morse theory: pg 534 to 537 (pg 13 to 16 of the PDF) Calum I attempted to discuss the Morse stratification and the construction of the stable and unstable manifolds of a critical point. The notes that I presented are uploaded here .
3/12/20 Section 1: Equivariant Morse theory pg 537 to pg 539 (pg 16 to pg 18) Calum I finished presenting the material on the Morse strata. The notes that I used have been updated here.
10/12/20 Section 2: Topology of gauge group pg 539 to 542 (pg 18 to 21 of the PDF) Luuk Luuk nicely summarised the materal from the paper and gave some useful background material on the tools being used behined the scenes to establish the results.
17/12/20 Section 2: Topology of gauge group pg 543 to 545 (pg 22 to 24 of the PDF) Luuk Luuk gave a nice introduction to complex K-theory. For those of us with less experience with K-theory this was a chance to see the prerequisites for understanding this section of the paper. I think that Luuk is going to send his notes round via email.
7/1/21 Section 2: The Yang-MillsTopology of gauge group pg 543 to 545 (pg 22 to 24 of the PDF) Luuk After a break for Christmas and New Year we will reconvene to finish up reading section 2. Luuk will return to finish the dicussion of Section 2.
14/1/21 Section 3:The Yang-Mills Functional Grigorios TBC
21/1/21 Section 4:The Yang-Mills equations Grigorios TBC
28/1/21 Section 5: Yang-Mills over a Riemann surface Lennart TBC
4/2/21 Section 5: Yang-Mills over a Riemann surface cont: Lennart TBC
11/2/21 Section 6: Representations of the Fundamental group cont: Lukas and Luuk TBC
18/2/21 Section 6: Representations of the Fundamental group cont: N/A general discussion TBC
25/2/21 Section 7: Holomorphic Vector bundles Lennart TBC
4/3/21 Section 7: Holomorphic Vector bundles cont: Lennart TBC
11/3/21 Section 8: Relation with Yang-Mills: TBC TBC

References