**Title:** On Furstenberg systems of some aperiodic multiplicative functions

**Speaker:** Mariusz Lemańczyk – Nicolaus Copernicus University in Toruń

**Abstract: **Studying arithmetic properties of multiplicative functions through the so called Furstenberg systems became a powerful and fruitful ergodic tool when dealing with the Sarnak and Chowla conjectures, cf. Frantzikinakis-Host’s theorem on the validity of logarithmic Sarnak’s conjecture for systems having not too many ergodic measures.

The Chowla conjecture, originally formulated for the Liouville function, was expected to hold for a much larger class of multiplicative functions in the sense that it has precisely one Furstenberg system, and this system is “maximally random”.

In 2015 Matomäki , Radziwiłł and Tao gave a counterexample to Elliot’s conjecture by constructing aperiodic multiplicative functions (bounded by 1) for which (already) the Chowla conjecture of order 2 fails.

During the talk I will try to describe recent results concerning a variety of Furstenberg systems for Matomäki, Radziwiłł, Tao’s functions, in particular, showing that the Chowla conjecture holds for them along some subsequences. The talk is based on my joint work with Alex Gomilko and Thierry de la Rue.

**Zoom link:** https://osu.zoom.us/j/98033590349

**Meeting ID:** 980 3359 0349

**Password:** Mixing

**Recorded Talk:** https://osu.zoom.us/rec/play/PSnnADgz3z7coGFSBSjBqrbhouGsBc5pHy_Y4tNGRq09SGk1UlLhd-xFZkOPSvRQG0d6qqc7ZUqaJZn7.z4J5lZq-XrTXCnPN?continueMode=true&_x_zm_rtaid=jIq7z5RFQZ-o8LQDfPiUrA.1617500870127.d8f12381bc2a272d1c51682f2c0006f0&_x_zm_rhtaid=771