On Saturday 24 October, from 10 am to noon, the UAB Faculty of Sciences and Biosciences hosted the entrance test for Bojos per les Matemàtiques 2027, the first step in the selection process. Bojos per les Matemàtiques is the mathematics course of Bojos per la Ciència, the programme through which the Fundació Catalunya La Pedrera brings research closer to upper-secondary students. It is organised by the Societat Catalana de Matemàtiques (SCM) in collaboration with the CRM, the UPC, the UAB and the UB.

After the test, the students went on a guided tour of the CRM with Pau Varela, the centre’s communication coordinator, who introduced them to the history of the CRM and the research carried out there.

Then Tomás Sanz (UB-CRM) gave the outreach talk “Les matemàtiques del so” (The mathematics of sound). Sanz began with the simplest signals and their properties, and then explained why studying how an iron bar heats up has made it possible to send WhatsApp voice messages efficiently, without using much data. The connection goes back to the French mathematician Joseph Fourier. In the early nineteenth century, while studying how heat spreads, Fourier proposed writing a function as a sum of simple waves, sines and cosines, an idea that met with Lagrange’s scepticism. Two centuries later, this way of breaking down a signal underpins much of sound processing, because an audio file can be stored as the set of waves that make it up, and those the ear can barely perceive can be discarded without anyone noticing.

Sanz, a tenure-track lecturer in the Department of Mathematics and Computer Science at the UB and a researcher affiliated with the CRM, earned his PhD at the UPC and has worked as a mathematician at research centres and universities in Bilbao, Edinburgh and Madrid. His research is on partial differential equations, the very family the heat equation belongs to. On his website, music and mathematical modelling also appear among his interests.

The selected students will be announced from 23 November and will start the course on 9 January. According to the provisional calendar, the course will run over nineteen Saturdays until 5 June, at the UPC School of Mathematics and Statistics, the UAB, the UB Faculty of Mathematics and Computer Science and, on the last day, the Museu del Tèxtil i l’Aigua in Manresa.

Five of the nineteen sessions will be given by four CRM researchers. Pablo Nicolás, a PhD student at the CRM, will give the two on non-Euclidean geometry, on 23 and 30 January. In February, Natàlia Castellana (UAB-CRM) will introduce them to topology and, a week later, Marc Masdeu (UAB-CRM) will talk to them about the prime numbers we use every day without realising it. The closing session, on 5 June in Manresa, will be given by Gemma Huguet (UPC-CRM), who will present the mathematical models that help explain how the brain decides when the information it receives is ambiguous.

In May, Albert Granados, the course coordinator, will devote two sessions to the mathematics of sound, the same topic as Saturday’s talk.