Gongfest 2025
So Long, and Thanks for All the Fish
Info
- Date: Thursday 26th June 2025
- Location: University of Wollongong
- Room: 35.G45 - Campus map
- Dinner location: Samaras Restaurant
- Transport: North Wollongong train station is a 15 minute walk from campus. There is also a free shuttle bus between the university and the station (routes 9 and 9N). There are free buses (routes 55A and 55C) that circumnavigate the city and stop at the main campus.
Schedule
Click on speaker names for abstracts.
| Time | Event |
|---|---|
| 9:20 | Opening |
| 9:30 | Adam Rennie |
| 10:00 | Eva-Maria Hekkelman |
| 10:30 | Morning Tea |
| 11:00 | Galina Levitina |
| 11:30 | Serge Richard |
| 12:00 | Lunch |
| 13:30 | Anne Thomas |
| 14:00 | Murray Elder |
| 14:30 | Afternoon Tea |
| 15:00 | Nathan Brownlowe |
| 15:30 | Aidan Sims |
| 16:00 | UniBar |
| 18:30 | Dinner |
Talks
- 9:30 — Adam Rennie (University of Wollongong)
Index theory in the Gong – [Slides]
Abstract: A lot of people did a lot of index theory and related maths in the Gong between 2012 and today. These were mostly PhDs, honours students and visitors, with the odd postdoc thrown in. This talk will take a tour through the mathematical highlights and the characters responsible. No names have been changed to protect the guilty.
- 10:00 — Eva-Maria Hekkelman (University of New South Wales)
Connes' Integration Formula of 1915 – [Slides]
Abstract: On a noncommutative space, we can do 'integration' with a construction called the noncommutative integral. This is based on an analogy with Connes' integration formula from 1988. I will attempt to convince you that Szegő already proved Connes' theorem in 1915, at least on the circle, and only if you really squint your eyes. Probably more useful is that Szegő's version can be generalised way beyond the circle case, leading to a noncommutative version of Szegő's limit theorem. Based on recent joint work with Ed McDonald.
- 11:00 — Galina Levitina (Australian National University)
Magnetic Fields and Spectral Shifts: Hitchhiking Near Landau Levels
Abstract: The spectral structure of magnetic Schrödinger and Dirac operators in constant magnetic field is characterized by sequences of threshold energies, commonly known as Landau levels, which correspond to eigenvalues of infinite multiplicity. In this talk, I will explore the behaviour of the three-dimensional Dirac operator in the presence of a constant magnetic field, perturbed by a short-range electric potential. Specifically, I will describe the asymptotic behaviour of the spectral shift function near these Landau levels. No towel required.
- 11:30 — Serge Richard (Nagoya University) – [Slides]
Scattering theory and operator algebras: a fruitful exchange
Abstract: After recalling the main definitions of scattering theory, we shall show how these two subjects have recently interacted: operator algebras provides the framework, scattering theory brings the substance. Several examples will be introduced, and a few questions will be raised.
- 13:30 — Anne Thomas (University of Sydney) – [Slides]
Right-angled Coxeter groups and Hecke C*-algebras
Abstract: Right-angled Coxeter groups are generated by a collection of reflections, so that each pair of reflections either commutes or generates an infinite dihedral group. The associated Hecke algebra is a classical deformation of the group algebra, and the C*-algebraic version of the Hecke algebra was introduced by Davis, Dymara, Januszkiewicz and Okun in 2007. Since then, Hecke C*-algebras have been extensively studied. This talk will mention my joint work with Thomas Lam but will mainly survey results by other people.
- 14:00 — Murray Elder (University of Technology Sydney) – [Slides]
Self-similar groups at GAGTA 2025
Abstract: I will report on some of the talks at the most recent GAGTA (geometric and asymptotic group theory with applications) held 9-13 June 2025, in particular, talks (not mine) that mention new results about self-similar groups.
- 15:00 — Nathan Brownlowe (University of Sydney) – [Slides]
Totally tubular, dude!
Abstract: Tannaka–Krein duality is an extension of Pontryagin duality to the setting of noncommutative compact groups, and it says that a compact group can be reconstructed from a category of representations of the group. This duality theory has a very successful generalisation to the world of quantum groups, including to a duality theory for Woronowicz's compact quantum groups. I will report on current work with Dave Robertson (UNE) where we look at a combinatorial model for the representation category associated to the quantum automorphism group of an infinite homogeneous rooted tree.
- 15:30 — Aidan Sims (University of Wollongong)
Gong-grown groupoids gone gangbusters
Abstract: In 2008, groupoid C*-algebras constituted a bit of a niche topic. These days it’s anything but, and the OANCG group at UOW—students, postdocs, visitors and staff—has been consistently involved in that change. I’ll tell bits of the tale of the development of groupoid C*-algebras and Cartan subalgebras over the last 15 years or so, highlighting the involvement of the ‘Gong group.
