Calendar

Feb
19
Wed
Colloquium: Jeremy Hoskins (Yale U.) @ Keller 401
Feb 19 @ 3:30 pm – 4:30 pm

Speaker: Jeremy Hoskins (Yale U)

Title: Elliptic PDEs on regions with corners

Abstract: Many of the boundary value problems frequently encountered in the simulation of physical problems (electrostatics, wave propagation, fluid dynamics in small devices, etc.) can be solved by reformulating them as boundary integral equations. This approach reduces the dimensionality of the problem, and enables high-order accuracy in complicated geometries. Unfortunately, in domains with sharp corners the solution to both the original governing equations as well as the corresponding boundary integral equations develop singularities at the corners. This poses significant challenges to many existing integral equation methods, typically requiring the introduction of many additional degrees of freedom. In this talk I show that the solutions to the Laplace, Helmholtz, and biharmonic equations in the vicinity of corners can be represented by a series of elementary functions. Knowledge of these representations can be leveraged to construct accurate and efficient Nyström discretizations for solving the resulting integral equations.The performance of these methods will be illustrated with several numerical examples.

Feb
20
Thu
Colloquium: Tingran Gao (U. Chicago) @ Keller 401
Feb 20 @ 3:00 pm – 4:00 pm


Speaker: Tingran Gao (U. Chicago)
Title: Manifold Learning on Fibre Bundles

Abstract:

Spectral geometry has played an important role in modern geometric data analysis, where the technique is widely known as Laplacian eigenmaps or diffusion maps.

In this talk, we present a geometric framework that studies graph representations of complex datasets, where each edge of the graph is equipped with a non-scalar transformation or correspondence.

This new framework models such a dataset as a fibre bundle with a connection, and interprets the collection of pairwise functional relations as defining a horizontal diffusion process on the bundle driven by its projection on the base.

The eigenstates of this horizontal diffusion process encode the “consistency” among objects in the dataset, and provide a lens through which the geometry of the dataset can be revealed. We demonstrate an application of this geometric framework on evolutionary anthropology.

Feb
21
Fri
Logic seminar: David Webb (II)
Feb 21 @ 2:30 pm – 3:30 pm
Colloquium: Max Alekseyev (George Washington U) @ Keller 401
Feb 21 @ 3:30 pm – 4:00 pm


SPEAKER: Max Alekseyev (George Washington U)
TITLE:
Transfer-Matrix Method as a Combinatorial Hammer:
Enumeration of Silent Circles, Graph Cycles, and Seating Arrangements

ABSTRACT:
I will discuss application of the transfer-matrix method to a variety
of enumeration problems concerning the party game “silent circles”,
Hamiltonian cycles in the antiprism graphs, simple paths/cycles in
arbitrary graphs, and generalized menage problem. While this method
does not always lead to nice formulas, it often provides an efficient
way of computing the corresponding quantities.

BIO:
Max Alekseyev is an Associate Professor of Mathematics and
Computational Biology at the George Washington University. He holds
M.S. in mathematics (1999) and Ph.D. in computer science (2007), and
is a recipient of the NSF CAREER award (2013) and the John Riordan
prize (2015). Dr. Alekseyev’s research interests range from discrete
mathematics (particularly, combinatorics and graph theory) to
computational biology (particularly, comparative genomics and genome
assembly). He is an Editor-in-Chief of the Online Encyclopedia of
Integer Sequences (http://oeis.org).

Feb
28
Fri
Logic seminar: Umar Gaffar
Feb 28 @ 2:30 pm – 3:30 pm
Mar
6
Fri
ISITA talk
Mar 6 @ 1:30 pm – Mar 6 @ 2:30 pm

The ISITA 2020 conference on coding and information theory
will be held at Ko Olina on October 24-27, 2020.
     http://www.isita.ieice.org/
The organizers are meeting in Hawaii this week, and have
agreed to give two talks at UH:

   Friday, March 6, 1:30pm–2:15pm in Keller Hall 413
   Speaker: Prof. Akiko Manada
   Shonan Institute of Technology

   Monday, March 9, 1:30pm–2:15pm in Keller Hall 413
   Speaker: Prof. Takayuki Nozaki
   Department of Informatics,
   Yamaguchi University

Each talk will be followed by refreshments and a problem
session. You are cordially invited to attend.

Mar
9
Mon
ISITA talk
Mar 9 @ 1:30 pm – Mar 9 @ 2:30 pm

The ISITA 2020 conference on coding and information theory
will be held at Ko Olina on October 24-27, 2020.
     http://www.isita.ieice.org/
The organizers are meeting in Hawaii this week, and have
agreed to give two talks at UH:

   Friday, March 6, 1:30pm–2:15pm in Keller Hall 413
   Speaker: Prof. Akiko Manada
   Shonan Institute of Technology

   Monday, March 9, 1:30pm–2:15pm in Keller Hall 413
   Speaker: Prof. Takayuki Nozaki
   Department of Informatics,
   Yamaguchi University

Each talk will be followed by refreshments and a problem
session. You are cordially invited to attend.

Mar
13
Fri
Logic seminar: Jack Yoon
Mar 13 @ 2:30 pm – 3:30 pm