Every democratic election rests on a simple promise: each voice counts, and each counts equally. But between casting our ballots and announcing a result lies a piece of mathematics that is far less innocent than it looks.
In the first part of this talk we elect a single winner. A hundred voters with fixed preferences, five candidates, five perfectly reasonable voting methods – and five different winners. We will see how a candidate with no chance can decide an election, and why a famous theorem by the Nobel laureate Kenneth Arrow shows that no voting system can be fair in every sense at once.
In the second part we fill a parliament. Seats come in whole numbers, so votes must be rounded, and rounding turns out to be surprisingly political. A party can lose a seat when the parliament gets bigger. A region can lose representation even though its population grew. The methods Europe’s parliaments actually use, such as D’Hondt or Sainte-Laguë, each make a different trade-off between these pitfalls.
The goal is not to lose faith in democracy, but to understand the choices hidden inside it. No mathematical background is needed – only curiosity and a willingness to count to 100.
Key Takeaway: Attendees will gain insight into how mathematical principles and different voting methods shape election outcomes and influence the allocation of parliamentary seats.
Date: Tuesday, 24 November 2026
Time: 11:00 – 12:00 CEST
Format: Online Lecture + Live Q&A
Audience: Free and open to everyone (students, researchers, professionals, and general public)
Register here
Register by 23 November!
Please keep in mind that the link to the Zoom platform, you’ll receive one day before the online lecture.
Dr. Michael J. Winckler has been the Administrative Director of the Interdisciplinary Center for Scientific Computing (IWR) at Heidelberg University since 2016 and of the Heidelberg Graduate School for Mathematical and Computational Methods in the Sciences (HGS MathComp) since 2007. A mathematician and computer scientist by training, his research interests lie in numerical methods for modelling, simulation and optimisation (MSO), in visualisation, and in digital humanities methods. He is the coordinator of the 4EU+ Flagship 3: Digitisation - Modelling - Transformation.