Tue, 24 Nov 2026

15:00 - 16:00
C3

TBA

Prof. Cris Moore
(Santa Fe Institute)
Tue, 17 Nov 2026

15:00 - 16:00
C3

TBA

Vedanta Thapar
((Mathematical Institute University of Oxford))
Tue, 10 Nov 2026
15:00
C3

TBA

Dr. Antoine Vendeville
(MediaLab Sciences Po)
Tue, 03 Nov 2026

15:00 - 16:00
C3

TBA

Joe Bacchus George
(University of Cambridge)
Tue, 27 Oct 2026

15:00 - 16:00
C3

Permutation-Invariant Spectral Learning via Dyson Diffusion

Tassilo Schwarz
((Mathematical Institute University of Oxford))
Abstract

Diffusion models are central to generative modeling and have been adapted to graphs by diffusing adjacency matrix representations. The challenge of having up to $n!$ such representations for graphs with $n$ nodes is only partially mitigated by using permutation-equivariant learning architectures. Despite their computational efficiency, existing graph diffusion models struggle to distinguish certain graph families and their spectra, unless graph data are augmented with ad hoc features.
This shortcoming stems from enforcing the inductive bias within the learning architecture.
In this work, we leverage random matrix theory to analytically extract the spectral properties of the diffusion process, allowing us to push most of the inductive bias from the architecture into the dynamics. Building on this, we introduce the Dyson Diffusion Model, which employs Dyson's Brownian motion to capture the spectral dynamics of an Ornstein-Uhlenbeck process on the adjacency matrix.
Furthermore, conditioned on the spectral dynamics, we formulate a Lie group diffusion, appropriately modeling the remaining degrees of freedom. Strikingly, the resulting learning problem becomes permutation invariant at the Lie algebra level.
We demonstrate that the Dyson Diffusion Model learns graph spectra accurately and outperforms existing graph diffusion models.
This is joint work with Cai Dieball, Constantin Kogler, Renaud Lambiotte, Arnaud Doucet, Aljaz Godec, and George Deligiannidis.

Paper: Schwarz, T., Dieball, C., Kogler, C., Lambiotte, R., Doucet, A., Godec, A., Deligiannidis, G., 2026, Permutation-Invariant Spectral Learning via Dyson Diffusion, Accepted at NeurIPS 2026

Tue, 20 Oct 2026

15:00 - 16:00
C3

Topology shapes dynamics of higher-order networks

Prof. Ginestra Bianconi
(School of Mathematical Sciences Queen Mary University of London)
Abstract
Complex systems like the brain, climate, and next-generation artificial intelligence rely on interactions that extend beyond simple pairwise relationships. This talk reveals the critical role of the topology encoded by higher-order networks in shaping  their dynamics.
 
By combiniging algebraic topology with non-linear dynamics, this research highlights how topological signals, dynamical variables defined on nodes, edges, triangles, and other higher-order structures, drive phenomena such as Topological Synchronization. The surprising result that emerges from this research is that topological operators including the Topological Dirac operator, offer a common language for treating complexity, AI algorithms, and quantum physics.  
These findings not only advance the understanding of the underlying mechanisms in neuroscience and climate science but also pave the way for very innovative machine learning algorithms inspired by theoretical physics. 
 
Millán, A.P., Sun, H., Giambagli, L., Muolo, R., Carletti, T., Torres, J.J., Radicchi, F., Kurths, J. and Bianconi, G., 2025. Topology shapes dynamics of higher-order networks. Nature Physics, pp.1-9.
Tue, 13 Oct 2026

15:00 - 16:00
C3

Invasion graphs: the networks behind how ecological communities assemble

Dr. Violeta Calleja Solanas
(Department of Biology, Oxford University)
Abstract
Ask a complex systems’ researcher to draw an ecological network and you will likely get an interaction network: nodes are species, and links are who eats whom / who competes with whom / who pollinates whom, etc. But behind every ecological community hides a second network, the invasion graph. Each node is an entire community (a set of species able to persist together) and each directed link is an invasion: a newcomer species arrives, tries to establish, and sometimes extinguishes residents. Community assembly becomes a walk on this graph, and the graph’s structure records every history the community could have had. 
In this talk, I will show how to build these graphs from generalised Lotka–Volterra dynamics and present the relationships between the structure of the invasion graph and the structure of the interaction networks among species. 
Wed, 11 Nov 2026
17:00
Lecture Room 1

Does Mathematics Have Anything to do With Biology? - Philip Maini

Philip Maini
(Mathematical Institute, University of Oxford)
Further Information

No two subjects in the sciences are presented as being more different than mathematics and biology, so this is a very fair question to ask, especially as here, "mathematics" does not include statistics, while "biology" includes physiology, medicine etc. This talk will illustrate how mathematics has had a profound impact in biology.

Examples will include Alan Turing's groundbreaking work on biological pattern formation (which Philip has actually applied to football shirt patterns), Alan Hodgkin and Andrew Huxley's Nobel Prize winning explanation for neuronal signalling, and potentially new therapies for certain cancers.

Philip Maini is Professor of Mathematical Biology and Director of the Wolfson Centre for Mathematical Biology in Oxford.

Please email @email to register to attend in person.

The lecture will be broadcast on the Oxford Mathematics YouTube Channel on Wednesday 02 December at 5-6 pm and any time after (no need to register for the online version).

The Oxford Mathematics Public Lectures are generously supported by XTX Markets.

Mathematrix is a student-led group in the Mathematical Institute where postgraduates and postdocs discuss and explore topics related to challenges in academic life and being a minority in the maths community. Below are details of the Welcome Lunch and the term card for the Michaelmas term.

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