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 course
Geometry & Topology Seminar, ‘Non-additivity of the unknotting number‘
Date and time: Wednesday 11th March, 12 pm – 1 pm
Location: SMRI Seminar Room (A12 Macleay Room 301)
Speaker: Hans Boden, McMaster University
Abstract: Every knot diagram can be converted into an unknot diagram by applying crossing changes. For a given knot, the minimum number of crossing changes needed, taken over all representative diagrams, is the unknotting number of that knot. In 1937 Wendt studied the unknotting number of composite knots, namely those of the form K # J. He posited that the unknotting number of K # J should be equal to the sum of the unknotting numbers of K and and that of J. Early evidence in support of the conjecture came from Marty Scharlemann, who in 1985 proved it for knots K, J with unknotting number one. The goal of the talk is to survey two recent preprints disproving the conjecture. The preprints are due to Mark Brittenham and Susan Hermiller, and their discovery has been a major breakthrough and suggests that knot theorists really do not understand unknotting at all well!
SMRI Seminar, ‘Mapping class groups and algebraic cycles‘
Date and time: Thursday 12th March, 1 pm – 2 pm
Location: SMRI Seminar Room (A12 Macleay Room 301)
Speaker: Richard Hain, Duke University
Abstract: The topology, geometry and arithmetic of moduli spaces of curves are well known to be intertwined. Many geometric properties of algebraic curves are reflected in the topology and geometry of the corresponding moduli space. In this talk I will give an overview of one aspect of this connection — namely results that relate algebraic cycles on powers C^n of a genus g curve C to the structure of the mapping class group of a closed surface of genus g. This is a subject with a rich history with roots in the work of Riemann and Abel in the 19th century.
I will review relevant background material, including the definition of and basic results about mapping class groups and algebraic cycles. I will explain why cycles that are defined for all curves, such as those defined by Ceresa and Gross–Schoen, are related to the Torelli subgroups of mapping class groups. If time permits, I will describe a new (higher) algebraic cycle defined for hyperelliptic curves that Wanlin Li and I have constructed.
SMRI Seminar
Date and time: Thursday 26th March, 1 pm – 2 pm
Location: SMRI Seminar Room (A12 Macleay Room 301)
Speaker: Hwayeon Ryu, Elon University
Seminar on Canonical Bases in Representation Theory
Dates and times: Wednesdays from 10 am –12 pm for the seminar, followed by a weekly exercise session from 1 pm –2 pm, starting from Wednesday 4th March, 2026
Location: SMRI Seminar Room (A12 Macleay Room 301)
Details: In this seminar, we aim to study the answers of the following motivating questions regarding irreducible representations of semisimple Lie algebras and related structures:
- How can we compute their characters?
- How can we compute tensor product decompositions?
- What are “canonical bases” for these modules?
A powerful tool introduced in the early 1990s, known as the canonical basis (Lusztig) or crystal basis (Kashiwara), provides a model to answer these questions.
We will start by learning about prototypical constructions that serve as motivation, before proceeding to the construction and properties of these modern bases: first studying Lusztig’s approach, and then Kashiwara’s approach.
This seminar will focus on the main ingredients and recipes used to motivate, construct and describe these bases: Kazhdan-Lusztig bases, Gelfand-Tsetlin bases, Lusztig’s algebraic construction, Lusztig’s geometric/topological construction, and Kashiwara’s crystal/global bases. More information on the Canonical Bases in Representation Theory website.
International Day of Mathematics Events:
Public Lecture: ‘A world from a sheet of paper’ by Tadashi Tokieda
Speaker: Tadashi Tokieda, Stanford University
Date and time: Friday 13th March 2026, 5:30 pm – 6:30 pm, followed by light refreshments
Location: Lecture Theatre 321, SWHB, The University of Sydney
Abstract: Starting from just a sheet of paper, by folding, stacking, crumpling, tearing, we shall explore a rich variety of phenomena, from magic tricks and geometry through elasticity and the traditional Japanese art of origami to medical devices and ‘h-principle’. Much of the lecture consists of table-top demos.
This public lecture is hosted by the Sydney Mathematical Research Institute as part of our program for International Day of Mathematics/ Pi Day. The talk will be tailored to a general audience and suitable for individuals from Year 10 onward. This is a free event, however registration is essential.
Maths at the Museum (Including ‘A magic show’ by Tadashi Tokieda)
To celebrate International Day of Mathematics, the Sydney Mathematical Research Institute (SMRI) will take over the Chau Chak Wing Museum (CCWM) with fun family activities across the weekend. The official theme of the International Day of Mathematics in 2026 is “Mathematics and Hope”. Across the weekend we will explore mathematical concepts with talks, panels, children’s activities in our Maths Craft Room as well as A magic show by Tadashi Tokieda (Stanford University).
This integrated program of interactive maths activities will run across the weekend, coinciding with the opening weekend of the Biennale at the Museum! Please check back as more events are added!
Date and time: Saturday 14th and Sunday 15th March, 12 pm – 4 pm
Location: Chau Chak Wing Museum, The University of Sydney
SMRI’s International Day of Mathematics Colloquia by Tadashi Tokieda
Colloquium 1: Irrational ways of manufacturing numbers
Friday 13th March 12 pm – 1 pm
This is meant to be light mathematical entertainment, exploring simple yet unusual phenomena involving rational, irrational, transcendental numbers. We will also glean a few open problems.
Colloquium 2: Pure mathematics as applied physics
Monday 16th March 2 pm – 3 pm, followed by afternoon tea
Humans tend to be better at physics than at mathematics. When an apple falls from a tree, there are more people who can catch it — they sense physically how the apple moves — than people who can compute its trajectory from a differential equation. Applying physical ideas to discover and explain mathematical results is therefore natural, even if it has seldom been tried in the history of science. The exceptions include Archimedes, some old Russian sources, a recent book of Mark Levi’s, as well as articles and lectures by yours truly. Many examples will be presented.
Presented by the Sydney Mathematical Research Institute as part of our International Day of Mathematics program. For catering purposes, please register your interest in one or both events.