Thu, 20 Oct 2022
14:00
L6

A tale of 2-groups: Dp(USp(2N)) theories

Alessandro Mininno
(Universität Hamburg)

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Abstract

After a brief introduction, I elucidate a technique, dubbed "bootstrap'', which generates an infinite family of D_p(G) theories, where for a given arbitrary group G and a parameter b, each theory in the same family has the same number of mass parameters, same number of marginal deformations, same 1-form symmetry, and same 2-group structure. This technique is utilized to establish the presence or absence of the 2-group symmetries in several classes of D_p(G) theories. I, then, argue that we found the presence of 2-group symmetries in a class of Argyres-Douglas theories, called D_p(USp(2N)), which can be realized by Z_2-twisted compactification of the 6d N=(2,0) of the D-type on a sphere with an irregular twisted puncture and a regular twisted full puncture. I will also discuss the 3d mirror theories of general D_p(USp(2N)) theories that serve as an important tool to study their flavor symmetry and Higgs branch.

Thu, 13 Oct 2022
14:00
L6

1-form symmetry versus large N QCD

Theodore Jacobson
(University of Minnesota)

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Abstract

It has long been appreciated that in QCD-like theories without fundamental matter, confinement can be given a sharp characterization in terms of symmetry. More recently, such symmetries have been identified as 1-form symmetries, which fit into the broader category of generalized global symmetries.  In this talk I will discuss obstructions to the existence of a 1-form symmetry in large N QCD, where confinement is a sharp notion. I give general arguments for this disconnect between 1-form symmetries and confinement, and use 2d scalar QCD on the lattice as an explicit example.  

Thu, 06 Oct 2022
14:00
N3.12

Gravitational Regge bounds

Kelian Haring
(Cern)

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Abstract

I will review the basic assumptions and spell out the arguments that lead to the bound on the Regge growth of gravitational scattering amplitudes. I will discuss the Regge bounds both at fixed transfer momentum and smeared over it. Our basic conclusion is that gravitational scattering amplitudes admit dispersion relations with two subtractions. For a sub-class of smeared amplitudes, black hole formation reduces the number of subtractions to one. Finally, I will discuss bounds on local growth derived using dispersion relations. This talk is based on https://arxiv.org/abs/2202.08280.

Wed, 05 Oct 2022
17:00
Lecture Theatre 1, Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, OX2 6GG

The million-dollar shuffle: symmetry and complexity - Colva Roney-Dougal

Colva Roney-Dougal
(University of St Andrews)
Further Information

In 1936, Alan Turing proved the startling result that not all mathematical problems can be solved algorithmically. For those which can be, we still do not always know when there's a clever technique which could give us the answer quickly. In particular, the famous "P = NP" question asks whether, for problems where the correct solution has a proof which can easily be checked, in fact there's a quick way to find the answer.

Many difficult problems become easier if they have symmetries: finding the shortest route to deliver many parcels would be easy if all the houses were neatly arranged in a circle. This lecture will explore the interactions between symmetry and complexity.

Colva Roney-Dougal is Professor of Pure Mathematics at the University of St Andrews and Director of the Centre for Interdisciplinary Research in Computational Algebra.

Please email @email to register.

The lecture will be available on our Oxford Mathematics YouTube Channel on 12 October at 5 pm.

The Oxford Mathematics Public Lectures are generously supported by XTX Markets.

Tue, 22 Nov 2022
14:00
L6

Character sheaves and Khovanov-Rozansky homology

Kostiantyn Tolmachov
(Edinburgh University)
Abstract

Khovanov-Rozansky homology is a link invariant that categorifies the HOMFLY-PT polynomial. I will describe a geometric model for this invariant, living in the monodromic Hecke category. I will also explain how it allows to identify objects representing graded pieces of Khovanov-Rozansky homology, using a remarkable family of character sheaves. Based on joint works with Roman Bezrukavnikov.

Moving beyond landscape resistance: considerations for the future of connectivity modelling and conservation science
Unnithan Kumar, S Turnbull, J Hartman Davies, O Hodgetts, T Cushman, S Landscape Ecology volume 37 2465-2480 (13 Aug 2022)
Polynomial bounds for chromatic number. I. Excluding a biclique and an induced tree
Scott, A Seymour, P Spirkl, S Journal of Graph Theory volume 102 issue 3 458-471 (01 Mar 2023)
Fri, 25 Nov 2022

12:00 - 13:00
N3.12

Knutson's Conjecture on the Representation Ring

Diego Martin Duro
(University of Warwick)
Abstract

Donald Knutson proposed the conjecture, later disproven and refined by Savitskii, that for every irreducible character of a finite group, there existed a virtual character such their tensor product was the regular character. In this talk, we disprove both this conjecture and its refinement. We then introduce the Knutson Index as a measure of the failure of Knutson's Conjecture and discuss its algebraic properties.

Thu, 03 Nov 2022

16:00 - 17:00
L3

Decentralised Finance and Automated Market Making: Optimal Execution and Liquidity Provision

Fayçal Drissi
Abstract

Automated Market Makers (AMMs) are a new prototype of 
trading venues which are revolutionising the way market participants 
interact. At present, the majority of AMMs are Constant Function 
Market Makers (CFMMs) where a deterministic trading function 
determines how markets are cleared. A distinctive characteristic of 
CFMMs is that execution costs for liquidity takers, and revenue for 
liquidity providers, are given by closed-form functions of price, 
liquidity, and transaction size. This gives rise to a new class of 
trading problems. We focus on Constant Product Market Makers with 
Concentrated Liquidity and show how to optimally take and make 
liquidity. We use Uniswap v3 data to study price and liquidity 
dynamics and to motivate the models.

For liquidity taking, we describe how to optimally trade a large 
position in an asset and how to execute statistical arbitrages based 
on market signals. For liquidity provision, we show how the wealth 
decomposes into a fee and an asset component. Finally, we perform 
consecutive runs of in-sample estimation of model parameters and 
out-of-sample trading to showcase the performance of the strategies.

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