Fri, 30 Jan 2026
12:00
Quillen Room N3.12

Three realisations of theta functions via the Heisenberg representation

Allan Perez Murillo
(University of Bristol)
Abstract
The classical theta functions appear throughout number theory, geometry, and physics, from Riemann’s zeta function to the projective geometry of abelian varieties. Despite these appearances, theta functions admit a unifying description under the lens of representation theory.
 
In this talk, I will explain how the Heisenberg representation, together with the Stone–von Neumann–Mackey theorem, provides a framework that
identifies three equivalent realizations of theta functions:
  • as holomorphic functions on certain symplectic spaces
  • as matrix coefficients of the Heisenberg (and metaplectic) representation,
  • as sections of line bundles on abelian varieties.
I will describe how these perspectives fit together and, if time permits, illustrate the equivalence through concrete one-dimensional examples. The
emphasis will be on ideas rather than technicalities. I will aim to make the talk self-contained, assuming familiarity with complex geometry and representation theory; background in Lie theory and harmonic analysis will be helpful but not essential.

Everyone is invited to join Mathematrix and the Mirzakhani Society for the launch party of the Oxford Women and Non-binary People in Mathematics Day (28 February). We’ll be in the South Mezzanine from 3 pm on Friday Jan 30 (following the official launch during Fridays@2) with coffee, tea, and sweet treats. Come along for a break and to learn all about OxWIM Day 2026.

Registrations for OxWIM Day is open. Find out more here.

The key lesson from the digital age is don't leave the best bit of your song or film until the end. In which case the Stone Roses would have had no chance. Standing Here is far from their best song (it was a B-Side) but the outro from 3.07 turns it in to gold. Skip the first 3.06 if you wish though it ain't so bad.

What do our Oxford Mathematics students do in their spare time?

Well, much the same as everyone else. Music, gym, bit of yoga, organising events, impersonating farmyard animals.

Tonbridge School is looking to recruit a number of Graduate Teachers to start at the school in September 2026. Details about the role, the school, and the market-leading package can be found in the attached job advert.

We are hosting an in-person event on Monday 26th January at The King’s Arms from 19:00-21:00 for anyone interested in chatting to current staff about the role.

The University of Leicester offers a fully funded PhD position in numerical linear algebra. Specifically, the project focuses on the so-called absolute value equations. You can find more about the project and how to apply at the following URL:

PROMYS Europe 2026: 12 July – 22 August.

Announcing PROMYS Europe 2026, a challenging six-week residential mathematics summer programme at the University of Oxford, UK.

F@2 WK2

 

Next week's Fridays@2 session highlights Women in Maths: Past, Present and Future!

Join the Mirzakhani Society to learn and celebrate the amazing work of female mathematicians, and hear more about the upcoming Women in Maths conference!

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