On the choice of interpolation scheme for neural CDEs
Morrill, J Kidger, P Yang, L Lyons, T Transactions on Machine Learning Research volume 2022 issue 9 (08 Sep 2022)
Thu, 20 Oct 2022
14:00
L6

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

Alessandro Mininno
(Universität Hamburg)

Note: we would recommend to join the meeting using the Zoom client for best user experience.

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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)

Note: we would recommend to join the meeting using the Zoom client for best user experience.

Further Information

It is possible to join online via Zoom.

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)
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