See the calendar below for future seminars and events.
Following every Thursday seminar, attendees are welcome to come to one of our SMRI Afternoon Teas which take place on Thursday afternoons at 2pm on the Quadrangle Terrace, accessed through the entry in Quadrangle Lobby P and via the SMRI Common Room on level 4.
Upcoming and current events: seminars, workshops and courses
SMRI Seminar, ‘From surfaces to 4-manifolds: a leisurely journey in the topology of manifolds‘
Speaker: Diarmuid Crowley, University of Melbourne
Date & time: Thursday 19 June 1 pm – 2 pm AEST
Location: SMRI Seminar Room (Macleay Building A12 Room 301)
Abstract: Let F be a closed connected orientable surface (2-manifold). Here are two foundational facts in the study of surfaces:
1) F_1 and F_2 are homeomorphic if and only if they have the same Euler characteristic;
2) Every self-homotopy equivalence of F is homotopic to a homeomorphism.
In this talk will I review these facts and then move to dimension 4, where the analogous statements for 4-manifolds are far from true. Indeed, in finding weak analogues of (1), i.e. necessary and sufficient conditions for two 4-manifolds within some class to be homeomorphic, it is often helpful to have counter-examples to the strict analogue of (2); i.e. self-homotopy equivalences of 4-manifolds which are not homotopic to homeomorphisms. The last part of this talk will contain a preliminary report on new examples of such “exotic self-homotopy equivalences”, which have shown up in joint work with Daniel Kasprowski, Mark Powell, and Arunima Ray.
Two seminars on random polytopes:
‘The diameter of polytopes and the Hirsch conjecture‘ (1/2)
Speaker: Geordie Williamson, University of Sydney
Date & time: Friday 20 June 9 am – 10 am AEST
Location: SMRI Seminar Room (Macleay Building A12 Room 301)
Abstract: Can one reasonably bound the diameter of the graph of a simple polytope? This is a fascinating open problem in combinatorial geometry. I’ll outline what is known, and in particular sketch Santos’ remarkable 2012 counter-example to the 50 year-old Hirsch conjecture. With the DeepMind team, we recently attacked this problem using machine learning. We made some progress, but this is not the focus of the talk. I want to communicate a simple problem where the right idea could be revolutionary.
‘A short survey on random polytopes‘ (2/2)
Speaker: Renjie Feng, University of Sydney
Date & time: Friday 20 June 10 am – 11 am AEST
Location: SMRI Seminar Room (Macleay Building A12 Room 301)
Abstract: Suppose we take random points in the plane from a Gaussian and look at the polytope they generate. What can I say about it? What is its expected volume, number of vertices, number of edges etc? This talk will provide an introduction to these kinds of questions. The focus is on many points in a fixed dimension, but some striking results where one allows the dimension to grow will also be touched upon.
Deligne-Lusztig Theory Learning Seminar
Speaker: In the spirit of the special semester on modern perspectives in representation theory, we are organising a learning seminar on Deligne-Lusztig theory.
Deligne and Lusztig (DL) gave a method to construct representation of reductive groups using l-adic cohomology, generalising parabolic induction. Later, this theory was used by Lusztig to find all representations of all finite simple groups of Lie type.
This seminar will focus on learning about the main ingredients and recipes to construct and describe these representations. Topics include reductive groups over finite fields, Frobenius maps, character theory, Harish-Chandra induction, l-adic cohomology, flag varieties, DL varieties, DL induction, character formulas, Lusztig series and more.
Dates & times: Wednesdays 10 am – 12 pm (lecture), followed by Wednesdays 1 pm – 2pm (exercise session). The first session, Wednesday 26th February, will be given by Charlotte Chan.
Location: SMRI Seminar Room (Macleay Building A12 Room 301)
Abstract: Tom Goertzen and Edmund Heng. Contact the organisers with any questions, or to join the mailing list.
Spaces, Functions and Numbers Seminar
Details: Welcome to Spaces, Functions and Numbers Seminar! This is a general-audience colloquium series for all members of the Sydney math community, including undergraduates at any level.
Dates & times: Tuesdays 4:30 pm – 6 pm AEST (in person talks), or 10 am – 11:30 am AEST (Zoom talks).
Location: In person events will run in the SMRI Seminar Room (Macleay Building A12 Room 301)
Organiser: June Park. Contact June with any questions, or to join the mailing list.
Informal Friday Seminar (IFS)
Details: The Informal Friday Seminar is a space where members of our research group can explain interesting things to each other in a casual setting. The rules of the seminar are the following:
- Any question/additional explanation from the audience is allowed.
- Ego out the window.
- Examples, examples, examples.
The seminar is intended to be conversational, so come ready to engage. If you choose to give an IFS talk, it’s important to know that part of the IFS philosophy is that learning is not linear. In other words, it if perfectly acceptable to give a talk that is a prerequisite for a talk that already happened.
Dates & times: Fridays 9 am – 11 am.
Location: SMRI Seminar Room (Macleay Building A12 Room 301)
Organiser: Finn Klein. For more details, see the IFS website.
Modern Perspectives in Representation Theory: Special Semester 2025
Organizers: Charlotte Chan (University of Michigan), Thomas Lam (University of Michigan), and Geordie Williamson (University of Sydney)
A special semester on “Modern Perspectives in Representation Theory” at the Sydney Mathematical Research Institute from May 5 through June 13, 2025. As part of the program, special events are planned for Week 3, May 19 – 23, and a conference running in Week 5, June 2 – 6.