Category: News

Back-to-the-lab day at the LIPN

On October 10, the laboratory held its back-to-school day. It was an opportunity to hear from new lab members, announce the year’s news and key deadlines, and take part in a bilingual theater play on inclusion in research.

Recently hired members of our lab gave these presentations:

  • Thomas Papastergiou (A3)  Machine learning and medical applications
  • Silvia di Gregorio (AOC)      Partial optimality in cubic correlation clustering
  • Florent Koechlin (CALIN)     Parikh automata and holonomic series
  • Morgan Rogers (LoVe)        Monoids and logic: what’s the connection?

Do you know about Arctic Circles

Wooden Arctic circles illustrating a theorem from Cohn, Larsen et Propp (1998 )
Wooden Arctic circles illustrating a theorem from Cohn, Larsen et Propp (1998 )

Here’s a wooden creation by Thomas Fernique, CNRS researcher at LIPN Lab. Small cubes are stacked in a large cube so that each stack is at least as high as those to its right and in front of it. In mathematics, this is called a plane partition.

The number of different configurations is gigantic, but the shape of a random one always seems about the same: chaotic inside a kind of circle and as “frozen” outside this circle.

In 1998, H. Cohn, M. Larsen and M. Propp proved that when the ratio of the sides of the large and small cubes grows, the border of the “frozen” zone tends towards a perfect circle: this is known as the “Arctic circle theorem.”