Zurich colloquium in mathematics

Modal title

Modal content

Please subscribe here if you would you like to be notified about these events via e-mail. Moreover you can also subscribe to the iCal/ics Calender.

Date / Time

Speaker

Title

Location

23 September 2025
16:30-18:15

Rob Morris
Instituto de Matemàtica Pura e Aplicada

Details

Title	An exponential improvement for diagonal Ramsey
Speaker, Affiliation	Rob Morris, Instituto de Matemàtica Pura e Aplicada
Date, Time	23 September 2025, 16:30-18:15
Location	KO2 F 150
Abstract	The Ramsey number R(k) is the minimum n such that every red-blue colouring of the edges of the complete graph on n vertices contains a monochromatic copy of K_k. It has been known since the work of Erdos and Szekeres in 1935, and Erdos in 1947, that 2^{k/2} < R(k) < 4^k, but until recently the only improvements were by lower order terms. In this talk I will give an introduction to the area, and also sketch the proof of a recent result, which improves the upper bound of Erdos and Szekeres by a (small) exponential factor. Based on joint work with Marcelo Campos, Simon Griffiths and Julian Sahasrabudhe.

An exponential improvement for diagonal Ramseyread_more

30 September 2025
16:30-18:15

Amnon Neeman
Università degli Studi di Milano

Details

Title	Vanishing negative K-theory and bounded t-structures
Speaker, Affiliation	Amnon Neeman, Università degli Studi di Milano
Date, Time	30 September 2025, 16:30-18:15
Location	KO2 F 150
Abstract	We will begin with a quick reminder of algebraic K-theory, and a few classical, vanishing results for negative K-theory. The talk will then focus on a striking 2019 article by Antieau, Gepner and Heller - it turns out that there are K-theoretic obstructions to the existence of bounded t-structures. The result suggests many questions. A few have already been answered, but many remain open. We will concentrate on the many possible directions for future research.

Vanishing negative K-theory and bounded t-structuresread_more

14 October 2025
16:30-18:15

Hong Wang
IHES and NYU Courant

Details

Title	Kakeya sets in R^3
Speaker, Affiliation	Hong Wang, IHES and NYU Courant
Date, Time	14 October 2025, 16:30-18:15
Location	KO2 F 150
Abstract	A Kakeya set is a compact subset of R^n that contains a unit line segment pointing in every direction. Kakeya set conjecture asserts that every Kakeya set has Minkowski and Hausdorff dimension n. We prove this conjecture in R^3 as a consequence of a more general statement about union of tubes. This is joint work with Josh Zahl.

Kakeya sets in R^3read_more

Archive: AS 25 SS 25 AS 24 SS 24 AS 23 SS 23 AS 22 SS 22 AS 21 SS 21 AS 20 SS 20 AS 19 SS 19 AS 18 SS 18 AS 17 SS 17 AS 16 SS 16 AS 15 SS 15 AS 14 SS 14 AS 13 SS 13 AS 12 SS 12 AS 11 SS 11 AS 10 SS 10 AS 09