Infosheet (March 14th, 2017) |
Queen's University - Department of Mathematics and Statistics |
Tuesday, March 14 |
Dynamics Seminar Time: 3.30 p.m. Place: Jeffery 422 |
Speaker: Bahman Gharesifard Title: Invariance Principle for Set-valued Dynamical Systems and an Application Abstract Attached |
Wednesday, March 15 |
Curves Seminar Time: 3:30 pm. Place: Jeffery 422 |
Speaker: Mike Roth Title: G-linearizations of line bundles Abstract Attached |
Thursday, March 16 |
Math Club Time: 5:30 p.m. Place: Jeffery 118 |
Speaker: Andrew McEachern Title: The 25 billion dollar eigenvalue Abstract Attached |
Friday, March 17 |
Number Theory Seminar Time: 10:30 a.m. Place: Jeffery 422 |
Speaker: Francesco Cellarosi Title: On the Riemann zeta function and Brownian excursions Abstract Attached |
Friday, March 17 |
Department Colloquium Time: 2:30 p.m. Place: Jeffery 234 |
Speaker: Jordan Watts, University of Colorado, Boulder Title: Quotients of Lie Group Actions Abstract Attached |
Monday, March 20 |
Seminar in Free Probability Time: 2:30 p.m. Place: Jeffery 202 |
Speaker: Yinzheng Gu, Queen’s University Title: Analytic subordination for bi-free convolution Abstract Attached |
Items for the Info Sheet should reach Anne ( burnsa@queensu.ca) by noon on Monday. The Info Sheet is published every Tuesday.
CALCULATOR EXAM POLICY , the official calculator is a Casio fx-991, or one with a blue sticker as issued by School of Business. All exam cover pages must only refer to these calculators only; any other exam cover, including other calculators (ie gold sticker) will not be accepted by the exams office. Proctors are going to be instructed to be less lenient with calculators that aren’t Casio fx-991 (or blue sticker from COMM), and will likely to be taking them away.
Tuesday, March 14, 3:30 p.m. Jeffery 422 - Dynamics Seminar
Speaker: Bahman Gharesifard
Title: Invariance Principle for Set-valued Dynamical Systems and an Application
Abstract: Invariance Principles for Set-valued Dynamical Systems and an Application Abstract: We state and prove an invariance principle for studying the stability of set-valued discrete-time dynamical systems, and discuss an application of this result for designing algorithms for balancing directed graphs, with only local information about their graph topology.
Wednesday, March 15, 3:30 p.m. Jeffery 422 - Curves Seminar
Speaker: Mike Roth
Title: G-linearizations of line bundles
Abstract: We will study when a line bundle on a projective variety admits a G-linearization.
Thursday, March 16, 5:30 p.m. Jeffery 118 - Math Club
Speaker: Andrew McEachern
Title: The 25 billion dollar eigenvalue
Abstract: Google's success derives in large part from its PageRank algorithm, which ranks the importance of web pages via search key words according to an eigenvector of a weighted matrix.
This talk will be an exposition of the PageRank algorithm, which uses standard linear algebra techniques and theorems you would see in any undergraduate classroom, such as the column stochasticity and a special case of the Perron-Frobenius Theorem.
Friday, March 17, 10:30 a.m. Jeffery 422 - Number Theory Seminar
Speaker: Francesco Cellarosi
Title: On the Riemann zeta function and Brownian excursions
Abstract: Following a 2001 paper by P. Biane, J. Pitman and M. Yor, I will review some results connecting the Riemann zeta function and the Jacobi theta function to some probability laws governing sums of independent exponential random variables. These laws are related to the 1-dimensional Brownian motion and higher dimensional Bessel processes.
Friday, March 17, 2:30 p.m. Jeffery 234 - Department Colloquium
Speaker: Jordan Watts
Title: Quotients of Lie Group Actions
Abstract: It is well-known that the orbit space of a compact Lie group action is a (local) semi-algebraic variety. The algebraic structure of this variety is obtained locally via invariant theory, and by a famous result of Schwarz we also obtain a differentiable structure on this space, and so we can do analysis on it as well. In fact, the differentiable structure determines the variety. There is a question of uniqueness: given a differentiable semi-algebraic variety that comes from a compact Lie group action, is there a unique compact Lie group action, up to some form of equivalence, that yields the variety? In general, the answer is "no". However, if we restrict our attention to group actions whose stabilizers are all finite (that is, orbifolds), then the answer is yes. We will talk about this result, as well as applications of it to circle actions; especially symplectic circle actions. In particular, symplectic quotients by such circle actions are never orbit spaces of Lie group actions unless they are orbifolds, with restrictions on when this can happen. This extends a result of Herbig-Schwarz-Seaton, which is concerned with orbifolds in a slightly more algebraic setting. This talk is designed for a general mathematical audience; no prior knowledge of symplectic or algebraic geometry, invariant theory, etc., is required.
Monday, March 20, 2:30 p.m. Jeffery 202
Seminar in Free Probability and Random Matrices
Speaker: Yinzheng Gu
Title: Analytic subordination for bi-free convolution
Abstract: We discuss some analytic properties of the additive bi-free convolution, both scalar-valued and operator-valued. We show that using the one-variable subordination functions associated with the additive free convolution, simple formulas for additive bi-free convolutions can be derived. As an application, we prove a result about atoms of the additive bi-free convolution.