Tue, 31 Jan 2023

14:00 - 15:00
L4

Hypercontractivity on compact Lie groups, and some applications

David Ellis
(University of Bristol)
Abstract

We present two ways of obtaining hypercontractive inequalities for low-degree functions on compact Lie groups: one based on Ricci curvature bounds, the Bakry-Emery criterion and the representation theory of compact Lie groups, and another based on a (very different) probabilistic coupling approach. As applications we make progress on a question of Gowers concerning product-free subsets of the special unitary groups, and we also obtain 'mixing' inequalities for the special unitary groups, the special orthogonal groups, the spin groups and the compact symplectic groups. We expect that the latter inequalities will have applications in physics.

Based on joint work with Guy Kindler (HUJI), Noam Lifshitz (HUJI) and Dor Minzer (MIT).

Tue, 24 Jan 2023

14:00 - 15:00
L4

Asymmetric graph removal

Yuval Wigderson
(Tel Aviv University)
Abstract

The triangle removal lemma of Ruzsa and Szemerédi is a fundamental result in extremal graph theory; very roughly speaking, it says that if a graph is "far" from triangle-free, then it contains "many" triangles. Despite decades of research, there is still a lot that we don't understand about this simple statement; for example, our understanding of the quantitative dependencies is very poor.


In this talk, I will discuss asymmetric versions of the triangle removal lemma, where in some cases we can get almost optimal quantitative bounds. The proofs use a mix of ideas coming from graph theory, number theory, probabilistic combinatorics, and Ramsey theory.


Based on joint work with Lior Gishboliner and Asaf Shapira.

Tue, 17 Jan 2023

14:00 - 15:00
L4

Expansion in supercritical random subgraphs of the hypercube and its consequences

Mihyun Kang
(Graz University of Technology)
Abstract

We consider a bond percolation on the hypercube in the supercritical regime. We derive vertex-expansion properties of the giant component. As a consequence we obtain upper bounds on the diameter of the giant component and the mixing time of the lazy random walk on the giant component. This talk is based on joint work with Joshua Erde and Michael Krivelevich.

Correction: Continuous Indexing of Fibrosis (CIF): improving the assessment and classification of MPN patients.
Ryou, H Sirinukunwattana, K Aberdeen, A Grindstaff, G Stolz, B Byrne, H Harrington, H Sousos, N Godfrey, A Harrison, C Psaila, B Mead, A Rees, G Turner, G Rittscher, J Royston, D Leukemia (12 Jan 2023)
Fri, 10 Feb 2023
16:00
L1

Mathematical models of curiosity

Professor Dani S Bassett
(J. Peter Skirkanich Professor, University of Pennsylvania)
Further Information

Dani Smith Bassett is an American physicist and systems neuroscientist who was the youngest individual to be awarded a 2014 MacArthur fellowship.

Bassett, whose pronouns are they/them,was also awarded a 2014 Sloan fellowship. They are currently the J. Peter Skirkanich Professor in the Departments of Bioengineering, Electrical & Systems Engineering, Physics & Astronomy, Neurology, and Psychiatry at the University of Pennsylvania and an external professor of the Santa Fe Institute. Their work focuses on applying network science to the study of learning in the human brain in addition to the study of other complex physical and biological systems.

Wikipedia

Abstract

What is curiosity? Is it an emotion? A behavior? A cognitive process? Curiosity seems to be an abstract concept—like love, perhaps, or justice—far from the realm of those bits of nature that mathematics can possibly address. However, contrary to intuition, it turns out that the leading theories of curiosity are surprisingly amenable to formalization in the mathematics of network science. In this talk, I will unpack some of those theories, and show how they can be formalized in the mathematics of networks. Then, I will describe relevant data from human behavior and linguistic corpora, and ask which theories that data supports. Throughout, I will make a case for the position that individual and collective curiosity are both network building processes, providing a connective counterpoint to the common acquisitional account of curiosity in humans.

 

 

Dimension results and local times for superdiffusions on fractals
Hambly, B Koepernik, P Stochastic Processes and their Applications volume 158 377-417 (18 Jan 2023)
Image from the lecture

The 'Introduction to University Mathematics' course is taken in the first two weeks of the first year of the Oxford Mathematics degree. It introduces the concepts and ways of mathematical thinking that students need in the years ahead. Much of the context will be familiar from high school but the way we think and write about it, and construct arguments and proofs, is more rigorous.

A data-driven market simulator for small data environments
Bühler, H Horvath, B Lyons, T Perez Arribas, I Wood, B (21 Jun 2020)
A generalised signature method for multivariate time series feature extraction
Morrill, J Fermanian, A Kidger, P Lyons, T (01 Jun 2020)
Wed, 01 Mar 2023

13:00 - 14:00
N3.12

Mathematrix: Targets vs Quotas

Abstract

We will discuss the pros and cons of targets vs quotas in increasing diversity in Mathematics.

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