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 Events
Cambridge
Wed 21 Aug 2019, 3:00pm SPECIAL
Probability Seminar
MATH 126
Supercritical percolation on nonamenable graphs
MATH 126
Wed 21 Aug 2019, 3:00pm-4:00pm

Abstract

Let G be a transitive nonamenable graph, and consider supercritical Bernoulli bond percolation on G. We prove that the probability that the origin lies in a finite cluster of size n decays exponentially in n. We deduce that:
  1. Every infinite cluster has anchored expansion almost surely. This answers positively a question of Benjamini, Lyons, and Schramm (1997).
  2. Various observables including the percolation probability and the truncated susceptibility are analytic functions of p throughout the entire supercritical phase.
Joint work with Jonathan Hermon.
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Tue 3 Sep 2019, 9:00am SPECIAL
MATX 1102
Qualifying Exams - Analysis
MATX 1102
Tue 3 Sep 2019, 9:00am-12:00pm

Details

For more information on Qualifying Exams, please visit http://www.math.ubc.ca/Grad/QualifyingExams/index.shtml
Lunch (pizza) will be provided in MATX 1101  for students writing the Analysis exam.
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Tue 3 Sep 2019, 1:00pm SPECIAL
MATX 1102
Qualifying Exams - Differential Equations
MATX 1102
Tue 3 Sep 2019, 1:00pm-4:00pm

Details

For more info, please visit http://www.math.ubc.ca/Grad/QualifyingExams/index.shtml
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Tue 3 Sep 2019, 1:00pm SPECIAL
MATX 1102
Qualifying Exams - Algebra
MATX 1102
Tue 3 Sep 2019, 1:00pm-4:00pm

Details

For more info, please visit http://www.math.ubc.ca/Grad/QualifyingExams/index.shtml
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Tue 3 Sep 2019, 4:30pm SPECIAL
MATH 125
Department Graduate Orientation
MATH 125
Tue 3 Sep 2019, 4:30pm-6:00pm

Details

Refreshments available.
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Zhejiang University
Thu 5 Sep 2019, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
Buchanan D307
TBA
Buchanan D307
Thu 5 Sep 2019, 3:30pm-4:30pm

Abstract

 
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University of Waterloo
Tue 10 Sep 2019, 4:00pm
Discrete Math Seminar
ESB 4127
TBA
ESB 4127
Tue 10 Sep 2019, 4:00pm-5:00pm

Abstract

 
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KAIST
Wed 11 Sep 2019, 3:00pm
Probability Seminar
TBA
A Generalization to DAGs for Hierarchical Exchangeability
TBA
Wed 11 Sep 2019, 3:00pm-4:00pm

Abstract

 

Motivated by problems in Bayesian nonparametrics and

probabilistic programming discussed in Staton et al. (2018), we

present a new kind of partial exchangeability for random arrays which

we call DAG-exchangeability. In our setting, a given random array is

indexed by certain subgraphs of a directed acyclic graph (DAG) of

finite depth, where each nonterminal vertex has infinitely many

outgoing edges. We prove a representation theorem for such arrays

which generalizes the Aldous-Hoover representation theorem.

 

In the case that the DAGs are finite collections of certain rooted

trees, our arrays are hierarchically exchangeable in the sense of

Austin and Panchenko (2014), and we recover the representation theorem

proved by them. Additionally, our representation is fine-grained in

the sense that representations at higher levels of the hierarchy are

also available. This latter feature is important in applications to

probabilistic programming, thus offering an improvement over the

Austin-Panchenko representation even for hierarchical exchangeability.

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Nassif Ghoussoub
UBC
Fri 13 Sep 2019, 3:00pm SPECIAL
PIMS Seminars and PDF Colloquiums
ESB 1012
PIMS-FIELDS-CRM Prize Lecture: TBA
ESB 1012
Fri 13 Sep 2019, 3:00pm-4:00pm

Abstract

TBA.

Note for Attendees

Light refreshments will be served in the PIMS lounge from 2:30p.m.
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University of Washington
Tue 17 Sep 2019, 4:00pm
Discrete Math Seminar
ESB 4127
TBA
ESB 4127
Tue 17 Sep 2019, 4:00pm-5:00pm

Abstract


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U. Bath
Wed 18 Sep 2019, 3:00pm
Probability Seminar
TBA
Wed 18 Sep 2019, 3:00pm-4:00pm

Abstract

 
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U. Bath
Fri 20 Sep 2019, 3:00pm
Department Colloquium
ESB 1012
Rising Stars Colloquium - TBA
ESB 1012
Fri 20 Sep 2019, 3:00pm-4:00pm

Abstract

 

Note for Attendees

Refreshments will be served at 2:30 p.m. in ESB 4133 (Lounge).
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UBC
Tue 24 Sep 2019, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
Buchanan D307
Eigenfunction decay rates for eigenvalues at threshold of essential spectrum
Buchanan D307
Tue 24 Sep 2019, 3:30pm-4:30pm

Abstract

 In the talk we present a new method for calculating decay rates of eigenfunctions for eigenvalues below the threshold of the essential spectrum. The method is also applicable for eigenvalues at the threshold provided that the eigenfunction exists. In fact, our a-priori bounds are the crucial first step for the proof that bound states at the thresholds exist. We consider the example of a helium atom and show that the decay rate of an eigenfunction at the threshold of the essential spectrum behaves as exp(− C􏰂|x|∞ ), where |x|∞ = max(|x|) is the maximum of electron coordinates. Moreover we show a similar result for the Froehlich Bipolaron.
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U. Chicago
Wed 25 Sep 2019, 3:00pm
Probability Seminar
Multiple SLE from a Loop Measure Perspective
Wed 25 Sep 2019, 3:00pm-4:00pm

Abstract

I will discuss the role of Brownian loop measure in the study of

Schramm-Loewner evolution. This powerful perspective allows us to apply

intuition from discrete models (in particular, the λ-SAW model) to the study of

SLE while simultaneously reducing many SLE computations to problems of

stochastic calculus. I will discuss recent work on multiple radial SLE that

employs this method, including the construction of global multiple radial SLE

and its links to locally independent SLE and Dyson Brownian motion. (Joint work

with Gregory F. Lawler.)

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Nick Olson-Harris
U. Waterloo
Tue 1 Oct 2019, 4:00pm
Discrete Math Seminar
ESB 4127
TBA
ESB 4127
Tue 1 Oct 2019, 4:00pm-5:00pm

Abstract


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UBC Math
Fri 4 Oct 2019, 3:00pm
Department Colloquium
ESB 1012
TBA
ESB 1012
Fri 4 Oct 2019, 3:00pm-4:00pm

Abstract


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Zhichao Wang
MPIM Bonn
Tue 8 Oct 2019, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
Buchanan D307
Recent developments of free boundary minimal hypersurfaces
Buchanan D307
Tue 8 Oct 2019, 3:30pm-4:30pm

Abstract

In this talk, I will introduce some recent developments of free boundary minimal hypersurfaces, including compactness, generic finiteness and index estimates. As an application, we also give the existence of infinitely many minimal hypersurfaces with non-empty free boundary under some weak assumptions. Part of the work is joint with Q.Guang, M.Li and X.Zhou
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Chris Ryan
Sauder, UBC
Tue 15 Oct 2019, 4:00pm
Discrete Math Seminar
ESB 4127
The discrete moment problem with nonconvex shape constraints
ESB 4127
Tue 15 Oct 2019, 4:00pm-5:00pm

Abstract

The discrete moment problem is a foundational problem in distribution-free robust optimization, where the goal is to find a worst-case distribution that satisfies a given set of moments. This paper studies the discrete moment problems with additional “shape constraints” that guarantee the worst-case distribution is either log-concave (LC), has an increasing failure rate (IFR), or an increasing generalized failure rate (IGFR). These classes of shape constraints have not previously been studied in the literature, in part due to their inherent nonconvexities. Nonetheless, these classes of distributions are useful in practice with applications in revenue management, reliability, and inventory control. We characterize the structure of optimal extreme point distributions. We show, for example, that an optimal extreme point solution to a moment problem with m moments and LC shape constraints is piecewise geometric with at most m pieces. 

This is joint work with Xi Chen (NYU, Stern School of Business), Simai He (Shanghai University of Finance and Economics, School of Information Management and Engineering), Bo Jiang (Shanghai University of Finance and Economics, School of Information Management and Engineering), and Teng Zhang (Stanford, Management Science and Engineering).
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Cornell University
Wed 16 Oct 2019, 4:00pm
Probability Seminar
TBA
Wed 16 Oct 2019, 4:00pm-5:00pm

Abstract

 
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Cornell University
Fri 18 Oct 2019, 3:00pm
Department Colloquium
ESB 1012
(PIMS/UBC distinguished colloquium) TBA
ESB 1012
Fri 18 Oct 2019, 3:00pm-4:00pm

Abstract

 

Note for Attendees

Refreshments will be served at 2:30 p.m. in ESB 4133 (Lounge).
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UBC Math
Fri 25 Oct 2019, 3:00pm
Department Colloquium
ESB 1012
TBA
ESB 1012
Fri 25 Oct 2019, 3:00pm-4:00pm

Abstract


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Brian Chan
UBC
Tue 29 Oct 2019, 4:00pm
Discrete Math Seminar
ESB 4127
TBA
ESB 4127
Tue 29 Oct 2019, 4:00pm-5:00pm

Abstract

 
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Fri 15 Nov 2019, 3:00pm
Department Colloquium
ESB 1012
(reserved for PIMS UBC Mathematical Sciences Young Faculty Award)
ESB 1012
Fri 15 Nov 2019, 3:00pm-4:00pm

Abstract

A link to be provided later.
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Thomas Hockenhull
University of Glasgow
Wed 20 Nov 2019, 2:45pm
Topology and related seminars
PIMS
TBA
PIMS
Wed 20 Nov 2019, 2:45pm-3:45pm

Abstract

 
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Tue 14 Jan 2020, 4:00pm
Discrete Math Seminar
ESB 4127
ESB 4127
Tue 14 Jan 2020, 4:00pm-5:00pm

Abstract


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