UBC

Thu 23 Oct 2014, 12:30pm
Graduate Student Seminar
Math 225

The probabilistic method

Math 225
Thu 23 Oct 2014, 12:30pm1:45pm
Abstract
The probabilistic method, pioneered by Paul Erdős, is a means of proving the existence of a certain object. By describing a random process of choosing objects, if there is a nonzero probability of making a successful choice, then necessarily the desired kind of object exists. We present a problem in discrete math that employs this method.
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SFU

Thu 23 Oct 2014, 3:30pm
Number Theory Seminar
room ASB 10900 (SFU  IRMACS)

On Jacobians of dimension 2g that decompose into Jacobians of dimension g

room ASB 10900 (SFU  IRMACS)
Thu 23 Oct 2014, 3:30pm4:30pm
Abstract
Let X be a genus 2g curve defined over an arbitrary field of characteristic not equal to 2 and let J(X) the Jacobian variety of X. We say that a Jacobian variety is decomposable if it is isogenous to a product of abelian varieties. The type of decomposition can by characterized by the type of kernel of the isogeny and the dimensions of the varieties in the product. We consider isogenies with kernel type (Z/2Z)^{g} and products of dimension g Jacobian varieties. Additionally, we insist that the isogeny is polarized. In this talk we describe a family of (nonhyperelliptic) genus 2g curves whose Jacobians are decomposable in this way. We prove that all genus 4 curves whose Jacobian has this decomposition type are either in this family or arise from a different construction considered by Legendre. Joint work with Nils Bruin.
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Department of Mathematics, University of South Carolina

Fri 24 Oct 2014, 3:00pm
Department Colloquium
MATX 1100

A new asymptotic enumeration technique: the Lovasz Local Lemma

MATX 1100
Fri 24 Oct 2014, 3:00pm4:00pm
Abstract
The lopsided version of the Lovasz Local Lemma gives asymptotically tight lower boundsfor a number of enumeration problems. In the configuration model matching upper bounds are available. In this way a number of asymptotic enumeration results, mostly due to Wormald and McKay, can be proved in an alternative way. A new result is asymptotic enumeration of graphs with respect to degree sequence and girth. A classical probabilistic result of Paul Erdos showed the existence of graphs with arbitrary large girth and chromatic number. If the degree sequence satisfies some mild conditions, we show that almost all graphs with this degree sequence and prescribed girth have high chromatic number.
This is joint work with Lincoln Lu.
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PennState

Mon 27 Oct 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

RozanskyWittentype invariants from symplectic Lie pairs

ESB 4127 (host: UBC)
Mon 27 Oct 2014, 3:00pm4:00pm
Abstract
In 1997, Rozansky and Witten built new finitetype invariants of 3manifolds from hyperkahler manifolds. It was later shown by Kontsevich and Kapranov that those invariants only depend on the holomorphic symplectic structure of the hyperkahler manifolds. Indeed Kapranov proved that these invariants may be considered as an analogue of ChernSimons type invariants, where the Atiyah class of the underlying complex manifold plays the role of Lie bracket. In this talk, we introduce symplectic structures on "Lie pairs" of (real or complex) algebroids, encompassing homogeneous symplectic spaces, symplectic manifolds with a $\mathfrak g$action and holomorphic symplectic manifolds. We show that to each such symplectic Lie pair are associated RozanskyWittentype invariants of threemanifolds. This is a joint work with Yannick Voglaire.
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UBC, Dept of Mathematics & CWSEI

Tue 28 Oct 2014, 12:30pm
Lunch Series on Teaching & Learning
MATH 126

Do we know how students view mathematics and how they study it?

MATH 126
Tue 28 Oct 2014, 12:30pm1:30pm
Abstract
It has long been known that the way a student views the subject they study affects the approach they take to studying
the subject. This, in turn, affects their performance in the subject. It seems, then, that the improvement of student
outcomes not only requires addressing the approach a student takes to study, but also their view of the subject. In this presentation, I will present results from a series of surveys intended to explore two separate, but related questions:
1. Do math instructors actually know how their students view math?
2. What approaches to study do students take and how do these relate to their achievement?
The crucial aspect of this work is that the data gathered was analysed by course year. It turns out that the answers to both questions above are different for lower and upperyear courses.
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Tue 28 Oct 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
ESB 2012

Traveling waves involving fractional Laplacians

ESB 2012
Tue 28 Oct 2014, 3:30pm4:30pm
Abstract
In this talk, we will discuss the existence of the traveling wave solution for the AllenCahn equation involving the fractional Laplacians. Based on the existence of the standing waves for the balanced AllenCahn equation, we will use the continuity method to obtain the existence of the traveling waves for unbalanced AllenCahn equation. The key ingredient is the the bound of the traveling speed in terms of the potential. Some open questions will be discussed.
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University of Utah

Wed 29 Oct 2014, 3:15pm
Topology and related seminars
ESB 4133

Constructing aspherical manifolds with a given fundamental group

ESB 4133
Wed 29 Oct 2014, 3:15pm4:15pm
Abstract
While an aspherical complex is determined up to homotopy by its
fundamental group, there are many geometrically different aspherical
manifolds with the same fundamental group. For instance, the punctured
torus and the pair of pants look quite different, but both have the same
fundamental group F_2. I will discuss constructions of aspherical
manifolds for a given fundamental group, talk about the smallest dimension
of such a manifold for a given group and describe some geometric
invariants that distinguish different aspherical manifolds with the same
fundamental group.
I will discuss this for right angled Artin groups (joint work with Mike
Davis, Boris Okun and Kevin Schreve) and possibly also for duality groups.
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Emory University

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

Hasse principles over function fields of padic curves

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)

Imaging with waves in complex environments (PIMSIAMUBC distinguished colloquium)

ESB 2012 (PIMS)
Fri 31 Oct 2014, 3:00pm4:00pm
Abstract
The talk is concerned with the application of sensor array imaging in complex environments. The goal of imaging is to estimate the support of remote sources or strong reflectors using time resolved measurements of waves at a collection of sensors (the array). This is a challenging problem when the imaging environment is complex, due to numerous small scale inhomogeneities and/or rough boundaries that scatter the waves. Mathematically we model such complexity (which is necessarily uncertain in applications) using random processes, and thus study imaging in random media. I will focus attention on the application of imaging in random waveguides, which exhibits all the challenges of imaging in random media. I will present a quantitative study of cumulative scattering effects in such waveguides and then explain how we can use such a study to design high fidelity imaging methods.
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UBC

Mon 3 Nov 2014, 3:00pm
Harmonic Analysis Seminar
Math 204

Restriction theory and quadratic equations in dense variables

Math 204
Mon 3 Nov 2014, 3:00pm4:00pm
Abstract
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Mathematics, Guelph

Mon 3 Nov 2014, 3:00pm
SPECIAL
Institute of Applied Mathematics
LSK 460

The Good, the Bad, and the Ugly: From Biofilms to Mathematics and Back Again

LSK 460
Mon 3 Nov 2014, 3:00pm4:00pm
Abstract
Bacterial biofilms are microbial depositions that form on immersed surfaces wherever environmental conditions sustain bacterial growth. They have been called the most successful life form on Earth and cities of microbes. Biofilms have important applications in environmental engineering, but are detrimental in a medical or industrial context. They have been characterised as both, spatially structured microbial populations, and as mechanical objects. Life in biofilm communities significantly differs from life in planktonic cultures. This is reflected in the complexity of mathematical models of biofilms that are essentially more involved than models of suspended microbial communities. In this talk I will focus on a class of highly degenerate diffusionreaction biofilm models. In its simplest form this includes simultaneously two nonlinear diffusion effects: (i) a porous medium equation like degeneracy when the dependent variable biomass density vanishes, and (ii) a superdiffusion singularity when it attains its {\it a priori} known upper bound. I will summarize some analytical (wellposedness) results, and discuss applications of the model to answer questions about biofilms by numerical simulations. I will hereby focus on the contribution of mathematical models (this and others) to understand the formation of clusterandchannel biofilm architectures, and I will illustrate how our model framework, extended by a model of bacterial communication by quorum sensing, can be used to shed light on the transition from an initial mode of biofilm colonization to a protected mode of biofilm growth.
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Kyoto University

Tue 4 Nov 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
ESB 2012

TBA

ESB 2012
Tue 4 Nov 2014, 3:30pm4:30pm
Abstract
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SFU

Tue 4 Nov 2014, 4:00pm
Discrete Math Seminar
ESB 4127

An infinite family of invWilfequivalent permutation pairs

ESB 4127
Tue 4 Nov 2014, 4:00pm5:00pm
Abstract
Wilfequivalence is one of the central concepts of patternavoiding permutations, and has been studied for more than thirty years. The two known infinite families of Wilfequivalent permutation pairs, due to StankovaWest and BackelinWestXin, both satisfy the stronger condition of shapeWilfequivalence. Dokos et al. recently studied a different strengthening of Wilfequivalence called invWilfequivalence, which takes account of the inversion number of a permutation. They conjectured that all invWilfequivalent permutation pairs arise from trivial symmetries. We disprove this conjecture by constructing an infinite family of counterexamples derived from the permutation pair (231) and (312). The key to this construction is to generalize simultaneously the concepts of shapeWilfequivalence and invWilfequivalence. A further consequence is a proof of the recent BaxterJaggard conjecture on evenshapeWilfequivalent permutation pairs.
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Bonn

Wed 5 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UAlberta)

TBA

ESB 4127 (host: UAlberta)
Wed 5 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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Thu 6 Nov 2014, 12:30pm
One Time Event
Room 200 of the Graduate Student Centre

Doctoral Exams

Room 200 of the Graduate Student Centre
Thu 6 Nov 2014, 12:30pm10:00am
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UBC

Thu 6 Nov 2014, 12:30pm
Graduate Student Seminar
Math 225

Supersymmetric integration

Math 225
Thu 6 Nov 2014, 12:30pm1:45pm
Abstract
We begin by defining the Grassmann integral of a function of both commuting ("bosonic") and anticommuting ("fermionic") variables. An important example is the mixed bosonicfermionic ("supersymmetric") Gaussian integral, which exhibits a surprising selfnormalization property. Time permitting, we will mention applications of the Grassmann integral to the representation of selfavoiding walk as a supersymmetric quantum field theory.
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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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UBC

Mon 10 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 10 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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UAlberta

Wed 12 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UAlberta)

TBA

ESB 4127 (host: UAlberta)
Wed 12 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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Morningside Center of Mathematics and Purdue

Thu 13 Nov 2014, 3:30pm
Number Theory Seminar
room MATH 126

Introduction to Mochizuki's works on interuniversal Teichmuller theory

room MATH 126
Thu 13 Nov 2014, 3:30pm4:30pm
Abstract
Interuniversal Teichmuller theory, as developed by Mochizuki in the past decade, is an analogue for number fields of the classical Teichmuller theory, and also of the padic Teichmuller theory of Mochizuki. In this theory, the ring structure of a number field is subject to nonring theoretic deformation. Absolute anabelian geometry, a refinement of anabelian geometry, plays a crucial role in interuniversal Teichmuller theory. In this talk, we will try to give an introduction to these ideas.
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UC Berkeley

Fri 14 Nov 2014, 3:00pm
Department Colloquium
MATX 1100

The fundamental theorem of arithmetic for metric measure spaces

MATX 1100
Fri 14 Nov 2014, 3:00pm4:00pm
Abstract
A metric measure space (mms) is simply a complete, separable metric space equipped with a probability measure that has full support. A fundamental insight of Gromov is that the space of such objects is much ``tamer'' than the space of complete, separable metric spaces per se because mms carry within themselves a canonical family of approximations by finite structures: one takes the random mms that arises from picking some number of points independently at random and equipping it with the induced metric and uniform probability measure. A natural (commutative and associative) binary operation on the space of mms is defined by forming the Cartesian product of the two underlying sets equipped with the sum of the two metrics and the product of the two probability measures. There is a corresponding notion of a prime mms and an analogue of the fundamental theorem of arithmetic in the sense that any mms has a factorization into countably many prime mms which is unique up to the order of the factors. Moreover, a rich Fourier theory enables one to analyze convolutions of probability measures on the space of mms and obtain counterparts of classical results in the theory of infinitely divisible and stable probability measures on Euclidean spaces due to L\'evy, It\^o, Hin\u{c}in, and LePage. This is joint work with Ilya Molchanov (Bern).
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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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UBC

Tue 18 Nov 2014, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
ESB 2012

TBA

ESB 2012
Tue 18 Nov 2014, 3:30pm4:30pm
Abstract
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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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The University of Auckland

Fri 21 Nov 2014, 3:00pm
Department Colloquium
Math Annex 1100

Reducing lectures, making students responsible, and offering semiauthentic mathematical experiences.

Math Annex 1100
Fri 21 Nov 2014, 3:00pm4:00pm
Abstract
In the Mathematics Department of The University of Auckland a major research project into undergraduate mathematics learning outcomes has required the development of three innovative ways to deliver undergraduate mathematics. One of these involves reducing lectures to less than one per week, handing responsibility for most of their mathematical learning to students using web or text resources. We then use the staff time saved to provide semiauthentic mathematical experiences in which students work in small groups for up to two hours at a time guided by a lecturer on openended mathematical situations. Such sessions require new teaching skills and new learning orientations. There is some evidence that we have made progress on the development of mathematical process skills.
Our research shows that, with our small trial groups, students perform at similar levels on the conventional assessments as do the students in the standard courses.
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UAlberta

Mon 24 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UBC)

TBA

ESB 4127 (host: UBC)
Mon 24 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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UAlberta

Wed 26 Nov 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UAlberta)

TBA

ESB 4127 (host: UAlberta)
Wed 26 Nov 2014, 3:00pm4:00pm
Abstract
TBA
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MIT

Wed 26 Nov 2014, 3:15pm
Topology and related seminars
ESB 4133


ESB 4133
Wed 26 Nov 2014, 3:15pm4:15pm
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Oxford University

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

TBA

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

Wed 3 Dec 2014, 3:00pm
CRG Geometry and Physics Seminar
ESB 4127 (host: UAlberta)

TBA

ESB 4127 (host: UAlberta)
Wed 3 Dec 2014, 3:00pm4:00pm
Abstract
TBA
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Sat 10 Jan 2015, 9:00am
SPECIAL
One Time Event
To Be Announced

Analysis  Qualifying Exams

To Be Announced
Sat 10 Jan 2015, 9:00am12:00pm
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Sat 10 Jan 2015, 1:00pm
SPECIAL
One Time Event
To Be Announced

Differential Equations  Qualifying Exams

To Be Announced
Sat 10 Jan 2015, 1:00pm4:00pm
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Sat 10 Jan 2015, 1:00pm
SPECIAL
One Time Event
To Be Announced Later

Algebra Qualifying Exams

To Be Announced Later
Sat 10 Jan 2015, 1:00pm4:00pm
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Brown University

Tue 13 Jan 2015, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
ESB 2012

TBA

ESB 2012
Tue 13 Jan 2015, 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
Refreshments will be served at 2:45pm in the Math Lounge area, MATH 125 before the colloquium.