Download November 24th, 2015

 INFO SHEET
QUEEN’S UNIVERSITY AT KINGSTON
Department of Mathematics and Statistics
http://www.mast.queensu.ca
November 24, 2015
CALENDAR
Thursday, November 26
Seminar on Free Probability
and Random Matrices
Friday, November 27
Time: 4:30 p.m.
Place: Jeffery 110
Number Theory Seminar
Friday, November 27
Time: 11:00 a.m.
Place: Jeffery 422
Department Colloquium
Monday, November 30
Time: 2:30 p.m.
Place: Jeffery 234
Algebraic Geometry Seminar
Time: 4:30 p.m.
Place: Jeffery 319
Speaker: Jamie Mingo, Queen’s University
Title: Second Order Cumulants of partially
Transposed Matrices
Abstract Attached
Speaker: Ernst Kani, Queen’s University
Title: The role of Hurwitz spaces in Cryptography
Abstract Attached
Speaker: Lin Song, Queen’s University
Title: Capacity of Communication Networks
Abstract Attached
Speaker: Alex Molnar, Queen’s University
Title: Constructing Calabi-Yau varieties
Abstract Attached
Items for the Info Sheet should reach Anne ([email protected]) by noon on Monday. The Info
Sheet is published every Tuesday.
Thursday, November 26, 4:30 p.m. Jeffery 110
Seminar on Free Probability and Random Matrices
Speaker: Jamie Mingo
Title: Second Order Cumulants of Partially Transposed Matrices
Abstract: I will review the construction of second order cumulants and work out the semi-circular case.
I will then show how to compute these for partially transposed Wishart matrices.
Seminar website: http://www.mast.queensu.ca/~mingo/seminar/
Friday, November 27, 11:00 a.m. Jeffery 422
Speaker: Ernst Kani
Title: The Role of Hurwitz spaces in Cryptography
Number Theory Seminar
Abstract: A recent result of C. Diem (2012) showed that Public Key Cryptosystems based on
hyperelliptic genus 3 curves are more secure than quartic genus 3 curves. On the other hand, by using a
method due to Donagi/Livne, Ben Smith showed that it is frequently possible to convert a hyperelliptic
system into a quartic system, thereby making it less secure. He also gave a heuristic (based on computer
data) for how often this is possible
In joint work with G. Frey (Essen) we investigated the Donagi/Livne/Smith construction from the point
of view of Hurwitz spaces (which classify curve covers) and were thus able to give a theoretical
explanation of Smith's heuristic.
In this talk I will first give some basic facts about security of Cryptosystems, and then explain how the
Donagi/Livne/Smith construction relates to curve covers and hence to Hurwitz spaces.
Friday, November 27, 2:30 p.m. Jeffery 234
Speaker: Lin Song
Title: Capacity of Communication Networks
Department Colloquium
Abstract: Network information theory deals with the fundamental limits of communication networks
and their corresponding achievable coding schemes. It extends Shannon's fundamental theorems for
point-to-point communication to the general multiuser setting. Although the theory is far from complete,
many elegant results have been developed. In this talk, some of these results will be presented. We start
from Shannon's capacity theorem for point-to-point communication channels, and then we discuss pointto-point communication with feedback, followed by discussions on multiple access channels, broadcast
channels and new preliminary results for two-way networks.
Monday, November 30, 4:30 p.m. Jeffery 319
Speaker: Alex Molnar
Title: Constructing Calabi-Yau varieties
Algebraic Geometry Seminar
Abstract: After the inception of (the conjectural) string theory, Calabi-Yau varieties have become very
interesting to both mathematicians and physicists, in particular, Calabi-Yau threefolds. Unfortunately,
they are incredibly difficult to study in full generality.
We will discuss a method to construct families of Calabi-Yau varieties from families of smaller
dimensional Calabi-Yau varieties, how these families are particularly amenable to study, and the
importance of this construction in string theory.