## Directions

We are located on the Main Campus of City in Northampton Square (map)

Getting to the Strand Campus:

• #### By underground

Thea nearest tube stops are Farringdon, Angel, also nearby is Barbican

• #### By train

Farringdon (10 minutes walk) or King's Cross stations (20 minutes walk) have nearest main-line services

• #### By bus

Buses stopping outside the College: : 4, 19, 30, 38, 43, 55, 56, 63, 73, 153, 205, 214, 243, 274, 341, 394, 476.

## Seminars at City, University of London

Found at least 20 result(s)

### 09.10.2013 (Wednesday)

#### An Update on Moonshine

Triangular Seminar Miranda Cheng (Paris VI)

 at: 16:30 City U.room AG07 abstract: In 2010, Eguchi--Ooguri--Tachikawa observed an unexpected relation between K3 elliptic genus and the sporadic group M24. In this talk I'll briefly review the recent developments on the topic of moonshine. In particular I will describe a more general relation between mock modular forms and finite groups, using Niemeier lattices as the starting point and including the M24 observation as a special case. I will also discuss various approaches in attempting to understand these mysterious relations, focusing on the study of compactification of heterotic strings on K3 surfaces. This talk will be based on joint work with Duncan--Harvey and with Dong--Harrison--Kachru--Whalen--Wrase.

### 08.10.2013 (Tuesday)

#### TBA

Regular Seminar Lionel Mason (Oxford)

 at: 16:00 City U.room C343 abstract:

### 01.10.2013 (Tuesday)

#### Unconsciously rational: optimal strategies in human mental searches in online auctions

Regular Seminar Andrea Baronchelli (City University London)

 at: 16:00 City U.room CG05 abstract: Characterizing how we explore abstract spaces is key to understand our (ir)rational behavior and decision making. While some light has been shed on the navigation of semantic networks, however, little is known about the mental exploration of metric spaces, such as the one dimensional line of numbers, prices, etc. Here we address this issue by investigating the behavior of users exploring the “bid space” in online auctions. We find that they systematically perform Lévy flights, i.e., random walks whose step lengths follow a power-law distribution. Interestingly, this is the best strategy that can be adopted by a random searcher looking for a target in an unknown environment, and has been observed in the foraging patterns of many species. In the case of online auctions, we measure the power-law scaling over several decades, providing the neatest observation of Lévy ﬂights reported so far. We also show that the histogram describing single individual exponents is well peaked, pointing out the existence of an almost universal behaviour. Furthermore, a simple model reveals that the observed exponents are nearly optimal, and represent a Nash equilibrium. We rationalize these ﬁndings through a simple evolutionary process, showing that the observed behavior is robust against invasion of alternative strategies. Our results show that humans share with the other animals universal patterns in general searching processes, and raise fundamental issues in cognitive, behavioural and evolutionary sciences.

### 29.01.2013 (Tuesday)

#### Uses of String Theory

Regular Seminar David Tong (DAMTP, Cambridge)

 at: 16:00 City U.room CG04 abstract:

### 23.01.2013 (Wednesday)

#### Large N vector Chern Simons theories and their Vasiliev duals part 1

Triangular Seminar Shiraz Minwalla (TIFR)

 at: 15:00 City U.room Geary abstract: In this talk we review recent developments in the study of $U(N)$ Chern Simons theories coupled to matter in the fundamental. The theories we study are not necessarily supersymmetric. These theories are interesting for several reasons. First, it turns out to be possible to exactly compute several quantities in these models in the t'Hooft large N limit at all values of the t'Hooft coupling $\lambda$. Second, these exact results strongly suggest that previously known Giveon-Kutasov type strong weak coupling dualities for supersymmetric theories extend to nonsupersymmetric theories. Third, several of these theories have conjectured bulk dual descriptions governed by Vasiliev's equations. Finally, theories with two gauge groups and matter in the bifundamental representation effectively reduce to fundamental models in the limit that one of the two gauge groups is much larger than the other, and so also have known Vasiliev dual descriptions. In the context of the N=6 ABJ theory, this observation allows us to find a Vasiliev dual of a field theory with a known string dual, and so realize Vasiliev theory as a limit of string theory.

### 23.01.2013 (Wednesday)

#### Large N vector Chern Simons theories and their Vasiliev duals part 2

Triangular Seminar Shiraz Minwalla (TIFR)

 at: 16:30 City U.room Geary abstract: In this talk we review recent developments in the study of $U(N)$ Chern Simons theories coupled to matter in the fundamental. The theories we study are not necessarily supersymmetric. These theories are interesting for several reasons. First, it turns out to be possible to exactly compute several quantities in these models in the t'Hooft large N limit at all values of the t'Hooft coupling $\lambda$. Second, these exact results strongly suggest that previously known Giveon-Kutasov type strong weak coupling dualities for supersymmetric theories extend to nonsupersymmetric theories. Third, several of these theories have conjectured bulk dual descriptions governed by Vasiliev's equations. Finally, theories with two gauge groups and matter in the bifundamental representation effectively reduce to fundamental models in the limit that one of the two gauge groups is much larger than the other, and so also have known Vasiliev dual descriptions. In the context of the N=6 ABJ theory, this observation allows us to find a Vasiliev dual of a field theory with a known string dual, and so realize Vasiliev theory as a limit of string theory.

### 11.12.2012 (Tuesday)

#### t.b.a.

Regular Seminar Anne Kandler (City)

 at: 16:00 City U.room CG04 abstract:

### 04.12.2012 (Tuesday)

#### t.b.a.

Regular Seminar Nick Dorey (DAMTP)

 at: 16:00 City U.room CG04 abstract:

### 27.11.2012 (Tuesday)

#### Sums, Restricted Sums and Differences

Regular Seminar David Penman (Essex)

 at: 16:00 City U.room CG04 abstract: Given a (nonempty) set $A$ of integers, two of the most obvious things to do with it are to form the sumset $A+A=\{a+b:\,a,b\in A\}$ and the difference set $A-A=\{a-b:\,a,b\in A\}$. One might also wish to consider the restricted sumset $A\hat{+}A=\{a+b:\,a,b\in A,\,a\neq b\}$. One can then ask various obvious questions about the relationships between the sizes of various of these sets and what this implies about structure, and I shall discuss some known results on this, including generalisations to more general contexts, e.g. in group theory. An intuition one might have is that the sumset/restricted sumset will be smaller than the difference set as addition is commutative but subtraction isn't: I shall survey various known results showing that this intuition is non-trivially wrong. At the end I shall discuss some recent constructions of sets $A$ which give new record large values of $\log(|A+A|)/\log(|A-A|)$. The original part of the talk is based on joint work with my research student Matthew Wells.

### 20.11.2012 (Tuesday)

#### C A N C E L L E D

Regular Seminar Gerard Watts (King's)

 at: 16:00 City U.room CG04 abstract:

### 13.11.2012 (Tuesday)

#### t.b.a.

Regular Seminar Tina Davies (Leeds)

 at: 16:00 City U.room CG04 abstract:

### 31.10.2012 (Wednesday)

#### t.b.a.

Regular Seminar Tamara Rogers (Arizona)

 at: 16:00 City U.room CG04 abstract:

### 30.10.2012 (Tuesday)

#### t.b.a.

Regular Seminar Jerome Gauntlett (Imperial)

 at: 16:00 City U.room CG04 abstract:

### 23.10.2012 (Tuesday)

#### t.b.a.

Regular Seminar Andrey Morozov (Leicester)

 at: 16:00 City U.room CG04 abstract:

### 16.10.2012 (Tuesday)

#### t.b.a.

 at: 16:00 City U.room CG04 abstract:

### 09.10.2012 (Tuesday)

#### Novel algebraic directions in Free Probability Theory

Regular Seminar Roland Friedrich (Humboldt)

 at: 16:00 City U.room CG04 abstract: Free probability theory, a species of non-commutative probability theory, is amazing for several reasons. Not only has it nice combinatorial features underlying it but also profound connections with other fields, in particular physics. Recently, we established a priori unexpected relations with some very prominent algebraic objects, in particular Hopf algebras. In this talk we will carefully introduce some of the basic features and give a glance at future directions.

### 14.06.2012 (Thursday)

#### Introduction to Quantum Sheaf Cohomology

Regular Seminar Eric Sharpe (Virginia Tech)

 at: 15:00 City U.room CG56 abstract: http://www.city.ac.uk/engineering-maths/research/mathematics-centre/research-seminars/seminars-2011-2012

### 27.03.2012 (Tuesday)

#### What happens when Lie groups meet integrable boundaries

Regular Seminar Niall MacKay (York)

 at: 16:00 City U.room CG04 abstract: When an integrable quantum field theory in one space dimension has a Lie group symmetry, the Lie algebra is typically embedded in a larger algebra called a Yangian. When one adds a boundary which preserves integrability, this is extended to a (generalized) twisted Yangian. We explain the role of these algebras in physics, and in particular recent work by MacKay and Regelskis which uncovers their governing role in the scattering of worldsheet excitations off D-branes in the AdS/CFT correspondence.

### 20.03.2012 (Tuesday)

#### A q-deformed Verlinde algebra

Regular Seminar Christian Korff (Glasgow)

 at: 16:00 City U.room CG04 abstract: We generalise a recent combinatorial description of the Verlinde or WZW fusion algebra of type A by defining cylindric Macdonald functions. The latter arise as weighted sums over non-intersecting paths on a square lattice with periodic boundary conditions. Expanding the cylindric Macdonald functions into Schur functions one obtains generalised Kostka-Foulkes polynomials. The latter contain ordinary Kostka-Foulkes polynomials, which appear in algebraic geometry, representation theory and combinatorics, as special case. We further motivate the cylindric Schur functions by showing that they are connected with a commutative Frobenius algebra which can be interpreted as a deformation of the Verlinde algebra: its structure constants are polynomials whose constant terms are the WZW fusion coefficients.

### 06.03.2012 (Tuesday)

#### E11 and generalised geometry

Regular Seminar Peter West (King's)

 at: 16:00 City U.room CG04 abstract: