Santa Clara University

Mathematics and Computer Science department

Colloquium Series

Winter 2015

Unless otherwise noted, talks will be at 3:50 PM in O'Connor 106.  Also, there will be refreshments before each talk in O'Connor 31 at 3:30 PM.


Tuesday, 24 February

Speaker:  Rachel Mudge and Nicole Gray, Foothill College

Title: Starting Strong: Setting the Stage For Meaningful Student Interaction



The presenters will discuss how, based on the Statway™ Starting Strong materials, they create a classroom environment of mutual respect, as well as a safe space for students to voice ideas, discuss strategies, and make mistakes and learn from them.

Tuesday, 3 March

Speaker: Bob Kleinhenz, Santa Clara University, Applied Math Dept

Title:  Long Strings of Atoms


Abstract:  The following problem is considered: A container holds NA atoms of type A and NB atoms of type B.  The atoms bond together randomly to form one long string of length N=NA+NB.  After the string has formed, and one end has been identified as the start, four bond types (reading from left to right) are present: a:A<=>A, b:A<=>B, c:B<=>A, and d:B<=>B.  It is of interest to materials researchers to count the number of strings containing a prespecified number of each bond types.

In this talk, a solution to this problem is presented that shows the interaction of combinatorics, linear algebra, and generating functions with a good dose of binomial coefficient identities tossed in along the way.  Time permitting, progress on the case of a three atom soup will be discussed.





---------------Fall 2014 ---------------------------


Tuesday, Oct 21st

Speaker:  John Stillwell, University of San Francisco

Title: What Does "Depth" Mean in Math?

Abstract:  Every mathematician believes that certain theorems are "deep," but the concept of depth does not have a formal definition. By looking at some famous theorems, ancient and modern, we will
study some candidates for "depth" at various levels, particularly
the undergraduate level. With these examples in hand we hope to
discuss whether any concepts of logic now available can give "depth"
a precise meaning.

Tuesday, Oct 28th

Speaker:  Timothy Hsu, San Jose State

Title: Cube complexes, 3-manifolds, and the Virtually Fibered Conjecture

Abstract:  Until recently, the Virtual Haken Conjecture was
probably the biggest open problem in 3-manifolds
(3-dimensional geometry).  Then, in March 2012, Ian Agol
proved a stronger version, known as the Virtually
Fibered Conjecture
, by completing a key part of Dani Wise's
program of studying nonpositively curved cube
.  So how were questions in 3-manifolds resolved
using spaces made from high-dimensional cubes?  We'll give
an overview explaining the connection and describe the
speaker's joint work with Wise that is part of the emerging
and rapidly growing subject of cube complexes.

Background: One semester of abstract algebra.  No topology
required; we will give at least cartoon definitions of the
relevant terms from topology (e.g., 3-manifold).

Tuesday, Nov 11th

Speaker:  Gregory Smith, Queen's University

Title: Nonnegative polynomials and sums of squares

Abstract:  A polynomial with real coefficients is nonnegative if it takes on only nonnegative values.  For example, any sum of squares is obviously nonnegative.  For a homogeneous polynomial with respect to the standard grading, Hilbert famously characterized when the converse holds, that is when every nonnegative homogeneous polynomial is a sum of squares.  After reviewing some history of this problem, we will examine this converse in more general settings.  This line of inquiry has unexpected connections to classical algebraic geometry and leads to new examples in which every nonnegative homogeneous polynomial is a sum of squares.  This talk is based on joint work with Grigoriy Blekherman and Mauricio Velasco.

Tuesday, Nov 18th

Speaker:  George Mohler, Santa Clara University

Title:  The inverse covariance matrix and applications to neural connectivity

*** A Pi Mu Epsilon Sponsored Event


Inferring connectivity of neurons in the brain is an active area of research and has applications to diagnosing neurodegenerative diseases and more generally understanding how connectivity leads to brain function.   In this talk we consider the problem of reconstructing unobserved neural connections from Calcium fluorescence time series observations at the neurons.  

We first will provide an introduction to the inverse covariance matrix, which is a useful tool for determining causality and connectivity in networks.  We will then show how inverse covariance can be adapted for neuroimaging data that may be noisy, low resolution, and exhibit synchronized firing.  In particular, we will develop a (relatively) simple algorithm with O(10) parameters that achieves state-of-the-art reconstruction accuracy compared to more complex models, along with an order of magnitude savings in computational cost.  We demonstrate the effectiveness of the algorithm using data from a recent Kaggle competition on neural network reconstruction.







Tuesday, TBA

Speaker:  Rachel Mudge and Nicole Gray, Foothill College

Title: How to Communicate with Students in Intentional Ways that Promote Motivation and Persistence



Tuesday, TBA

Speaker: Bob Kleinhenz, Santa Clara University, Applied Math Dept

Title:  Counting Atomic Strings with Matrices







If you have a disability and require a reasonable accommodation,
please call/email Rick Scott 408-554-4460/rscott at scu dot edu (or
use 1-800-735-2929 TTY—California Relay).

Abstracts of previous talks are available here.
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