02/03/2022

In Folha, Viana talks about the city of Lviv, in Ukraine.

Crédito: Pixabay

Reproduction of Marcelo Viana's column in Folha de S.Paulo

At the time of writing this column, the Ukrainian city of Lviv is under attack by the Russian army, but it still serves as a link between its country and the rest of Europe. The metropolis of 700,000 inhabitants, which was once Polish (Lwów) and Austro-Hungarian (Lemberg), doesn't usually make international headlines, but it has a rich history spanning more than 750 years.

Lviv also holds a special place in the annals of science, having hosted, in the 1930s, one of the most brilliant schools of mathematics that Europe has ever seen, with stars such as H. Steinhaus, S. Banach, K. Kuratowski, J. Schauder, S. Mazur, K. Borsuk, S. Ulam and M. Kac, among others. It's a story told over two cafes.

The story begins at Café Roma, near the university. It was there that the group would gather after the weekly meetings of the Polish Mathematical Society, for hours of discussion on set theory, general topology, functional analysis, and other topics, accompanied by a cup of tea or coffee. This forged a collaborative environment that seems natural today, but was uncommon in mathematical research at the time.

Although consumption at the Café was frugal, it wasn't always easy to pay the bill, especially towards the end of the month… One day, annoyed by the difficulty in obtaining credit at Roma, Banach decided to move the meeting to the Scottish Café, 20 meters away, where the group continued collaborating on solving mathematical problems.

Ulam recounts that the tables had marble tops, where it was possible to write directly with a pencil. But Banach's wife didn't appreciate this mess, so in 1935 she provided a large notebook for them to write down the problems and solutions, so that they wouldn't be forgotten. The Scottish Book, as it became known, is an almost legendary mathematical document.

To read the full text, visit the newspaper's website.