UBC

Mon 26 Sep 2016, 3:00pm
Algebraic Geometry Seminar
MATX 1102

Taking roots vs taking logarithms

MATX 1102
Mon 26 Sep 2016, 3:00pm4:00pm
Abstract
I will report on joint work with D. Carchedi, S. Scherotzke and N. Sibilla, about a comparison between two objects obtained from a fs log scheme over the complex numbers: the "infinite root stack" and the "KatoNakayama space". I will also hint at more recent work that explains how parabolic sheaves (with real or rational weights) interact with the picture.
I will be as little technical as possible and focus on examples rather than on the general theory.
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Division of Chemistry & Chemical Engineering and Engineering & Applied Science Caltech

Mon 26 Sep 2016, 3:00pm
Institute of Applied Mathematics
ESB 2012

The Swim Pressure of Active Matter

ESB 2012
Mon 26 Sep 2016, 3:00pm4:00pm
Abstract
One of the distinguishing features of many living systems is their ability to move, to selfpropel, to be active. Through their motion, either voluntarily or involuntarily, living systems are able selfassemble: birds flock, fish school, bacteria swarm, etc. But such behavior is not limited to living systems. Recent advances in colloid chemistry have led to the development of synthetic, nonliving particles that are able to undergo autonomous motion by converting chemical energy into mechanical motion and work – chemical swimming. This swimming or intrinsic activity imparts new behaviors to active matter that distinguish it from equilibrium condensed matter systems. For example, active matter generates its own internal pressure (or stress), which can drive it far from equilibrium and free it from conventional thermodynamic constraints, and by so doing active matter can control and direct its own behavior and that of its surroundings. In this talk I will discuss our recent work on swimmers and on the origin of a new source for stress that is responsible for selfassembly and pattern formation in active matter.
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UBC

Mon 26 Sep 2016, 3:00pm
Harmonic Analysis Seminar
MATH 126

Radial Fourier Multipliers

MATH 126
Mon 26 Sep 2016, 3:00pm4:00pm
Abstract
Let $m$ be a radial multiplier supported in a compact subset away from the origin. For dimensions $d\ge 2$, it is conjectured that the multiplier operator $T_m$ is bounded on $L^p(R^d)$ if and only if the kernel $K=\hat{m}$ is in $L^p(R^d)$, for the range $1<p<2d/(d+1)$. Note that there are no a priori assumptions on the regularity of the multiplier. This conjecture belongs near the top of the tree of a number of important related conjectures in harmonic analysis, including the Local Smoothing, BochnerRiesz, Restriction, and Kakeya conjectures. We discuss new progress on this conjecture in dimensions $d=3$ and $d=4$. Our method of proof will rely on a geometric argument involving sizes of multiple intersections of threedimensional annuli.
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UBC

Tue 27 Sep 2016, 3:30pm
Diff. Geom, Math. Phys., PDE Seminar
ESB 2012

Gibbs' measure and almost sure global wellposedness for one dimensional periodic fractional Schrodinger equation

ESB 2012
Tue 27 Sep 2016, 3:30pm4:20pm
Abstract
In this talk we will present recent local and global wellposedness results on the one dimensional periodic fractional Schrodinger equation. We will also talk about construction of Gibbs' measures on certain Sobolev spaces and how we can prove almost sure global wellposedness using this construction.
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UBC

Tue 27 Sep 2016, 4:00pm
Discrete Math Seminar
ESB 4127

SchurPositivity of Equitable Ribbons

ESB 4127
Tue 27 Sep 2016, 4:00pm5:00pm
Abstract
Schur functions form an important basis for the space of symmetric functions and show up in areas from representation theory to quantum mechanics. Given an appropriate diagram of boxes, we construct its corresponding Schur function by counting the numbers of tableaux: fillings of these boxes with positive integers that satisfy some simple conditions. We then form the Schurpositivity partially ordered set by comparing these numbers of tableaux. In this talk, we present some new results of how order relations in this partially ordered set can be derived from properties of the diagrams. We then present some progress toward longstanding conjectures.
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Oregon State University

Wed 28 Sep 2016, 3:00pm
Probability Seminar
ESB 2012

Some probability theory that arises from worrying about NavierStokes and other quasilinear equations

ESB 2012
Wed 28 Sep 2016, 3:00pm4:00pm
Abstract
The success of probability theory in the analysis of linear, or even certain semilinear, parabolic and elliptic pde’s is well documented. In spite of various attempts to find a stochastic foothold for the analysis of NavierStokes equations and related quasilinear equations, the problem remains a substantial challenge. That said, the quest can lead to new stochastic structures and problems that relate to modern probability in fundamental ways. In this talk I will try to indicate this with a few explicit examples largely stemming from the LejanSznitman multiplicative cascade/branching random walk framework for NavierStokes equations.
This talk is primarily based on recent joint work with Radu Dascaliuc, Nicholas Michalowski, and Enrique Thomann with partial support from the National Science Foundation.
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University of Illinois, Urbana–Champaign

Wed 28 Sep 2016, 3:15pm
Topology and related seminars
ESB 4133 (PIMS Lounge)

An equivariant motivic slice filtration

ESB 4133 (PIMS Lounge)
Wed 28 Sep 2016, 3:15pm4:15pm
Abstract
Mixing Voevodsky's filtration in motivic homotopy and Dugger's in C_2equivariant homotopy theory leads to an interesting filtration on the C_2equivariant motivic homotopy category. In this talk, I'll introduce these slice filtrations and talk about some joint work with P. A. Ostvaer, where we compute the resulting zero slice of the equivariant motivic sphere spectrum.
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UBC Math

Fri 30 Sep 2016, 3:00pm
Department Colloquium
ESB 2012

UBC Mathematics and PIMS Faculty Award Colloquium  On the local Langlands conjectures

ESB 2012
Fri 30 Sep 2016, 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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Note for Attendees
Tea beforehand in the PIMS lounge (ESB 4133)