University College London

Wed 3 Sep 2014, 3:00pm
Probability Seminar
ESB 2012

Gradient Gibbs measures with disorder

ESB 2012
Wed 3 Sep 2014, 3:00pm4:00pm
Abstract
We consider  in uniformly strictly convex potentials case  two versions of random gradient models. In model A) the interface feels a bulk term of random fields while in model B) the disorder enters though the potential acting on the gradients itself. It is well known that without disorder there are no Gibbs measures in infinite volume in dimension d = 2, while there are gradient Gibbs measures describing an infinitevolume distribution for the increments of the field, as was shown by Funaki and Spohn. Van Enter and Kuelske proved that adding a disorder term as in model A) prohibits the existence of such gradient Gibbs measures for general interaction potentials in d = 2. Cotar and Kuelske proved the existence of shiftcovariant gradient Gibbs measures for model A) when d > 2 and the expectation with respect to the disorder is zero, and for model B) when d > 1.
In recent work, we prove uniqueness of shiftcovariance gradient Gibbs measures with expected given tilt under the above assumptions. We also prove decay of covariances for both models.
We will also discuss in the talk the case of nonconvex potentials with disorder.
This is partly based on joint work with Christof Kuelske.
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UBC

Fri 5 Sep 2014, 3:00pm
Department Colloquium
Math Annex 1100

Remarks on the local Langlands conjectures.

Math Annex 1100
Fri 5 Sep 2014, 3:00pm4:00pm
Abstract
The Langlands program, initiated in the 1960s, is a set of conjectures predicting a unification of number theory and the representation theory
of groups. More precisely, the Langlands correspondence provides a way to interpret results in number theory in terms of group theory, and vice versa.
In this talk we sketch a few aspects of the local Langlands correspondence using elementary examples. We then comment on some questions raised by the emerging "mod p" Langlands program.
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Mon 8 Sep 2014, 3:00pm
SPECIAL
Institute of Applied Mathematics
LSK 306

Institute of Applied Mathematics Welcome Reception

LSK 306
Mon 8 Sep 2014, 3:00pm5:00pm
Abstract
Come join us for some food and drink to welcome in the new academic year. Meet old friends and new.
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UIUC

Mon 8 Sep 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 8 Sep 2014, 3:00pm4:00pm
Abstract
TBA
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Queensland

Mon 8 Sep 2014, 4:30pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

Preservation of depth in local geometric Langlands program

ESB 4127 (host: UBC)
Mon 8 Sep 2014, 4:30pm5:30pm
Abstract
Local geometric Langlands program aims to establish a relationship between representations of the Galois group of a local field and irreducible representations of the dual group. It is expected that, under mild conditions, this correspondence preserves depths of representations. In this talk, I will explain the geometric analogue of this expectation, in the framework of FrenkelGaitsgory's local geometric Langlands correspondence. Based on a joint project with TsaoHsien Chen: http://arxiv.org/abs/1404.0598
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EHESS, France

Tue 9 Sep 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar

The effect of a line with fast diffusion on biological invasions

Tue 9 Sep 2014, 3:30pm3:30pm
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Hokkaido University

Wed 10 Sep 2014, 3:00pm
Probability Seminar
ESB 2012

Critical twopoint function for the phi^4 model in dimensions d>4

ESB 2012
Wed 10 Sep 2014, 3:00pm4:00pm
Abstract
The (lattice) phi^4 model is a scalar fieldtheoretical model that exhibits a phase transition. It is believed to be in the same universality class as the Ising model. In fact, we can construct the phi^4 model as the N > infinity limit of the sum of N Ising systems (with the right scaling of spinspin couplings). Using this GriffithsSimon construction and applying the lace expansion for the Ising model, we can prove meanfield asymptotic behavior for the critical phi^4 twopoint function. In this talk, I will explain the key points of the proof, and discuss possible extensions of the results to the powerlaw coupling case.
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University of Washington

Thu 11 Sep 2014, 3:30pm
Number Theory Seminar
room K10908, IRMACS, SFU

Obstructions to the Hasse principle on degree 4 del Pezzo surfaces

room K10908, IRMACS, SFU
Thu 11 Sep 2014, 3:30pm4:30pm
Abstract
In 1970, Manin showed that the Brauer group can obstruct the existence of rational points. ColliotThélène and Sansuc have conjectured that this obstruction completely explains the failure of rational points on del Pezzo surfaces. We show that on degree 4 del Pezzo surfaces, this BrauerManin obstruction manifests itself through linear projections. As a consequence of the proof, we obtain a simple and efficient for computing the Brauer classes of a degree 4 del Pezzo surface. This is joint work with Anthony VárillyAlvarado.
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UBC

Fri 12 Sep 2014, 3:00pm
Department Colloquium
Math Annex 1100

[N choose k] equals [N choose Nk]

Math Annex 1100
Fri 12 Sep 2014, 3:00pm4:00pm
Abstract
We explore and take advantage of hidden structure behind the binomial identity above. This will lead us through some basic representation theory of sl(2), categorical equivalences and quantum knot invariants.
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Freiburg

Mon 15 Sep 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 15 Sep 2014, 3:00pm4:00pm
Abstract
TBA
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UBC Zoology and Mathematics

Mon 15 Sep 2014, 3:00pm
Institute of Applied Mathematics
LSK 460

Evolutionary Dynamics in HighDimensional Phenotype Spaces

LSK 460
Mon 15 Sep 2014, 3:00pm4:00pm
Abstract
Adaptive dynamics is a general framework to study longterm evolutionary dynamics. It is typically used to study evolutionary scenarios in lowdimensional phenotype spaces, such as the important phenomenon of evolutionary branching (adaptive diversification). I will briefly recall the basic theory of evolutionary branching and present a wellstudied empirical example. Because birth and death rates of individuals are likely to be determined by many different phenotypic properties, it is important to consider evolutionary dynamics in highdimensional phenotype spaces. I will present some results about evolutionary branching in highdimensional phenotype spaces, as well as results about more general types of nonequilibrium evolutionary dynamics, such as chaos. Finally, I will compare the deterministic adaptive dynamics in highdimensional phenotype spaces to individualbased simulations of the underlying stochastic birthdeath process.
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University of Washington

Tue 16 Sep 2014, 4:00pm
Discrete Math Seminar
ESB 4133

CoxeterKnuth Graphs and a signed Little map

ESB 4133
Tue 16 Sep 2014, 4:00pm5:00pm
Abstract
We propose an analog of the Little map for reduced expressions for signed permutations. We show that this map respects the transition equations derived from Chevellay's formula on Schubert classes. We discuss many nice properties of the signed Little map which generalize recent work of Hamaker and Young in type A where they proved Lam's conjecture. As a key step in this work, we define shifted dual equivalence graphs building on work of Assaf and Haiman and prove they can be characterized by axioms. These graphs are closely related to both the signed Little map and to the Coxeter Knuth relations of type B due to Kraskiewicz.
This talk is based on joint work with Zach Hamaker, Austin Roberts and Ben Young.
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National University of Mexico

Thu 18 Sep 2014, 3:15pm
SPECIAL
Topology and related seminars
ESB 4133

On the Chern classes of singular varieties

ESB 4133
Thu 18 Sep 2014, 3:15pm4:15pm
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Hebrew University of Jerusalem

Thu 18 Sep 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 18 Sep 2014, 3:30pm4:30pm
Abstract
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Hebrew University of Jerusalem

Fri 19 Sep 2014, 3:00pm
Department Colloquium
ESB 2012 (PIMS)

PIMSUBC Distinguished Colloquium, title TBA

ESB 2012 (PIMS)
Fri 19 Sep 2014, 3:00pm4:00pm
Abstract
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Bonn

Mon 22 Sep 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 22 Sep 2014, 3:00pm4:00pm
Abstract
TBA
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Mathematics, SFU

Mon 22 Sep 2014, 3:00pm
Institute of Applied Mathematics
LSK 460

Challenges and Opportunities in ”Mathematics for Industry”

LSK 460
Mon 22 Sep 2014, 3:00pm4:00pm
Abstract
Industrial mathematics is a field that spans a broad spectrum of activity ranging from applied R&D performed by mathematicians employed in industry, to purely academic research projects undertaken by university mathematics professors. In this talk, I will survey several research projects I have been involved with that fall under the heading of what I’ll call ”mathematics *for* industry”, which relates specifically to direct collaborations between university mathematicians and nonacademic partner organizations. These projects encompass a diverse collection of mathematical techniques (ranging from simple algebra to partial differential equations, finite volume methods, inverse problems and homogenization theory) as well as applications from many scientific disciplines (such as fluid mechanics, image processing, atmospheric science and plant biology). In the process, I will attempt to characterize the job of an industrial mathematician and to identify the qualities and skills that are most desirable for anyone interested in making significant contributions to research at the interface between university and industry. I also hope to convince you that industrial collaborations can be a rich source of challenging and novel mathematical problems for academic mathematicians.
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University of Paris XIII

Wed 24 Sep 2014, 3:15pm
Topology and related seminars
ESB 4133

TBA

ESB 4133
Wed 24 Sep 2014, 3:15pm4:15pm
Abstract
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UBC

Thu 25 Sep 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 25 Sep 2014, 3:30pm4:30pm
Abstract
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UBC

Fri 26 Sep 2014, 3:00pm
Department Colloquium
Mathematics Annex 1100

TBA

Mathematics Annex 1100
Fri 26 Sep 2014, 3:00pm4:00pm
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Stanford

Mon 29 Sep 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

Stabilization of discriminants in the Grothendieck ring

ESB 4127 (host: UBC)
Mon 29 Sep 2014, 3:00pm4:00pm
Abstract
We consider the ``limiting behavior'' of {\em discriminants}, by which we mean informally the closure of the locus in some parameter space of some type of object where the objects have certain singularities. We focus on the space of partially labeled points on a variety X, and linear systems on X. These are connected  we use the first to understand the second. We describe their classes in the "ring of motives", as the number of points gets large, or as the line bundle gets very positive. They stabilize in an appropriate sense, and their stabilization can be described in terms of the motivic zeta values. The results extend parallel results in both arithmetic and topology. I will also
present a conjecture (on ``motivic stabilization of symmetric powers'') suggested by our work. Although it is true in important cases, Daniel Litt has shown that it contradicts other hopedfor statements. This is joint work with Melanie Wood.
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Tue 30 Sep 2014, 2:30pm
Diff. Geom, Math. Phys., PDE Seminar

TBA

Tue 30 Sep 2014, 2:30pm3:30pm
Abstract
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Universite de CergyPontoise

Tue 30 Sep 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar

TBA

Tue 30 Sep 2014, 3:30pm4:30am
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Hong Kong University of Science and Technology

Wed 1 Oct 2014, 3:00pm
Probability Seminar
ESB 2012

Solving the highdimensional Markowitz Optimization Problem: a tale of sparse solutions

ESB 2012
Wed 1 Oct 2014, 3:00pm4:00am
Abstract
We consider the highdimensional Markowitz optimization problem. A new approach combining sparse regression and estimation of optimal returns based on random matrix theory is proposed to solve the problem. We prove that under some sparsity assumptions on the underlying optimal portfolio, our novel approach asymptotically yields the theoretical optimal return, and in the meanwhile satisfies the risk constraint. To the best of our knowledge, this is the first method that can achieve these two goals simultaneously in the highdimensional setting. We further conduct simulation and empirical studies to compare our method with some benchmark methods, including the equally weighted portfolio, the bootstrapcorrected method by Bai et al. (2009) and the covarianceshrinkage method by Ledoit and Wolf (2004). The results demonstrate substantial advantage of our method, which attains high level of returns while keeping the risk well controlled by the given constraint.
Based on joint work with Mengmeng Ao and Yingying Li.
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University of Paris XIII

Wed 1 Oct 2014, 3:15pm
Topology and related seminars
ESB 4133


ESB 4133
Wed 1 Oct 2014, 3:15pm4:15pm
Abstract
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Université Pierre et Marie Curie

Thu 2 Oct 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 2 Oct 2014, 3:30pm4:30pm
Abstract
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Université ParisSud

Thu 2 Oct 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
TBA

TBA

TBA
Thu 2 Oct 2014, 3:30pm4:30pm
Abstract
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Simon Fraser University

Wed 8 Oct 2014, 3:00pm
Probability Seminar
ESB 2012

Modelling and simulating systems with statedependent diffusion

ESB 2012
Wed 8 Oct 2014, 3:00pm4:00am
Abstract
We propose a framework for modelling stochastic systems with statedependent diffusion coefficients. Rather than specifying dynamics through a statedependent drift and diffusion coefficients, assuming detailed balance we specify an equilibrium probability density and a statedependent diffusion coefficient. We argue that our framework is more natural from the modelling point of view and has a distinct advantage in situations where either the equilibrium probability density or the diffusion coefficient is discontinuous. We introduce a numerical method for simulating dynamics in our framework that samples from the equilibrium probability density exactly and elegantly handles discontinuities in the coefficients. This is joint work with Xin Yang.
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Thu 9 Oct 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 9 Oct 2014, 3:30pm4:30pm
Abstract
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Harvard University

Fri 10 Oct 2014, 3:00pm
Department Colloquium
ESB 2012 (PIMS) Time and date to be confirmed

PIMSUBC Distinguished Colloquium, TitleTBA

ESB 2012 (PIMS) Time and date to be confirmed
Fri 10 Oct 2014, 3:00pm4:00pm
Abstract
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Thu 16 Oct 2014, 3:30pm
Number Theory Seminar
room MATH 126


room MATH 126
Thu 16 Oct 2014, 3:30pm4:30pm
Abstract
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Thu 23 Oct 2014, 3:30pm
Number Theory Seminar
room MATH 126


room MATH 126
Thu 23 Oct 2014, 3:30pm4:30pm
Abstract
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Emory University

Thu 30 Oct 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 30 Oct 2014, 3:30pm4:30pm
Abstract
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Univeristy of Michigan

Fri 31 Oct 2014, 3:00pm
Department Colloquium
ESB 2012 (PIMS)

PIMSIAMUBC distinguished colloquium

ESB 2012 (PIMS)
Fri 31 Oct 2014, 3:00pm4:00pm
Abstract
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UBC

Thu 6 Nov 2014, 3:30pm
Number Theory Seminar
room MATH 126

TBA

room MATH 126
Thu 6 Nov 2014, 3:30pm4:30pm
Abstract
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Berkeley

Fri 7 Nov 2014, 1:30pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Fri 7 Nov 2014, 1:30pm2:30pm
Abstract
TBA
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Thu 13 Nov 2014, 3:30pm
Number Theory Seminar
room MATH 126


room MATH 126
Thu 13 Nov 2014, 3:30pm4:30pm
Abstract
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Jussieu

Mon 17 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 17 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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Thu 20 Nov 2014, 3:30pm
Number Theory Seminar
room MATH 126


room MATH 126
Thu 20 Nov 2014, 3:30pm4:30pm
Abstract
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Thu 27 Nov 2014, 3:30pm
Number Theory Seminar
room MATH 126


room MATH 126
Thu 27 Nov 2014, 3:30pm4:30pm
Abstract
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Caltech

Fri 30 Jan 2015, 3:00pm
Department Colloquium
ESB 2012 (PIMS) TBA (time and date to be confirmed)

PIMSUBC distinguished colloquium

ESB 2012 (PIMS) TBA (time and date to be confirmed)
Fri 30 Jan 2015, 3:00pm4:00pm
Abstract
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Brown University

Fri 13 Mar 2015, 3:00pm
Department Colloquium
ESB 2012 (PIMS)

PIMSUBC Distinguished Colloquium, TitleTBA

ESB 2012 (PIMS)
Fri 13 Mar 2015, 3:00pm4:00pm
Abstract
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Note for Attendees
Today the seminar has two talks. Sheldon 34pm (as usual) and Masoud 4:305:30pm. Coffee and cookies are served in between.