Download November 10th, 2015

 INFO SHEET
QUEEN’S UNIVERSITY AT KINGSTON
Department of Mathematics and Statistics
http://www.mast.queensu.ca
November 10, 2015
CALENDAR
Wednesday, November 11
Wednesday, November 11
Thursday, November 12
Remembrance Day
Algebraic Geometry Seminar
Time: 3:00 p.m.
Place: Jeffery 319
Seminar on Free Probability
and Random Matrices
Friday, November 13
Time: 4:30 p.m.
Place: Jeffery 110
Number Theory Seminar
Friday, November 13
Time: 11:00 a.m.
Place: Jeffery 422
Department Colloquium
Time: 2:30 p.m.
Place: Jeffery 234
Classes cancelled from 10:30 am – 11:30 am for
Remembrance Day Service
Speaker: Owen Ren, Queen’s University
Title: Vector bundles over the projective line
Abstract Attached
Speaker: Josué Daniel Vázquez Becerra,
Queen’s University
Title: Second order freeness: a free probability
study of fluctuations of random matrices, Part III
Abstract Attached
Speaker: Peng-Jie Wong, Queen’s University
Title: On Heilbronn characters
Abstract Attached
Speaker: Serdar Yüksel, Queen’s University
Title: Convexity Properties, Existence and
Approximation of Optimal Solutions in
Decentralized Stochastic Control
Abstract Attached
Items for the Info Sheet should reach Anne ([email protected]) by noon on Monday. The Info
Sheet is published every Tuesday.
Wednesday, November 11, 3:00 p.m. Jeffery 319
Speaker: Owen Ren
Title: Vector bundles over the projective line
Algebraic Geometry Seminar
Abstract: We will prove that every vector bundle over the complex projective line splits into a direct
sum of line bundles and the isomorphism classes of the line bundles are (up to order) uniquely
determined. Our proof will basically follow Grothendieck’s 1957 argument.
Thursday, November 12, 4:30 p.m. Jeffery 110
Seminar on Free Probability and Random Matrices
Speaker: Josué Daniel Vázquez Becerra
Title: Second order freeness: a free probability study of fluctuations of random matrices, Part III
Abstract: Second order freeness is a feature exhibited in the large limit by random matrix ensembles
such as the orthogonal Gaussian random matrices and the orthogonal Wishart random matrices. Its main
purpose is to help determine the asymptotic behaviour of the covariance of traces of products of random
matrices; this is comparable to the description of the asymptotic behaviour of the expectation of the trace
of products of random matrices that we get from freeness.
Seminar website: http://www.mast.queensu.ca/~mingo/seminar/
Friday, November 13, 11:00 a.m. Jeffery 422
Speaker: Peng-Jie Wong
Title: On Heilbronn characters
Number Theory Seminar
Abstract: In this talk, I will start by reviewing some aspects of number theory, and then discuss
several properties of Heilbronn characters. If time allows, I will give an application to L-functions
attached to elliptic curves.
Friday, November 13, 2:30 p.m. Jeffery 234
Department Colloquium
Speaker: Serdar Yüksel
Title: Convexity Properties, Existence and Approximation of Optimal Solutions in Decentralized
Stochastic Control
Abstract: This talk is concerned with stochastic dynamic team problems and their optimal solutions.
First, a brief review on information structures in decentralized control will be presented. To facilitate a
convex analytical approach, strategic measures for team problems are introduced; these are probability
measures induced by admissible team policies. Properties such as convexity, compactness and Borel
measurability are studied. These lead to existence of and structural results for optimal policies. It is
shown that the set of strategic measures for a team problem is in general non-convex unlike single
decision maker control problems, but the extreme points of a relaxed set consist of deterministic team
policies, which lead to their optimality. Characterizations for convexity of problems which include
teams with a non-classical information structure will be presented. Finally, asymptotic optimality of
finite model representations for a large class of dynamic team problems will be established. These lead
to asymptotic optimality of quantized control policies, so that one can construct a sequence of finite
models obtained through the quantization of measurement and action spaces whose solutions converge
to the optimal cost. Witsenhausen's counterexample, an important problem considered in the literature,
will be discussed as a special case. (Part of this is joint work with Naci Saldi and Tamas Linder).