Department Colloquium

The Department of Mathematics at Western Michigan University presents colloquiua.

Time: Varies
Place: 6625 Everett Tower
 
Spring Semester 2020
Feb. 20: Gary Weiss, Ph.D., University of Cincinnati
Fall Semester 2019
Nov. 14: Ruriko Yoshida, Ph.D., Naval Postgraduate School
Nov. 7:  Jen Munson, Ph.D., Northwestern University
Oct. 24: David Bindel, Ph.D., Cornell University
Oct. 11: Kevin Dykema, Mattawan Schools

Spring 2020

Thursday, feb. 20

A Eureka Moment in the Theory of Commutators, Operators of the Form AB - BA, History and Consequences presented by Gary Weiss, Ph.D., University of Cincinnati

Time: 4:00 p.m.

Refreshments served at 3:50 p.m.

Abstract: Understanding operators on Hilbert space of the form AB-BA is essential in many parts of operator theory and its applications. This talk will describe some early problems and consequences of their solutions. But the focus will be on the evolution of a key simple sounding commutator question about a special 4 x 4 matrix and the evolution of its solution and its consequential complete characterizations of Hilbert space commutators.

Fall 2019

Thursday, Nov. 14

Tropical Principal Component Analysis on Tree Spaces presented by Ruriko Yoshida, Ph.D., Naval Postgraduate School

Time: 4:00 p.m.

Refreshments served at 3:50 p.m.

Abstract: In 2004, Speyer and Sturmfels showed that a space of phylogenetic trees with fixed set of leaves is a tropical linear space defined by the tropicalization of linear equations. It is thus natural to apply tropical arithmetics to conduct statistical analyses over a tree space under the tropical metric, such as tropical principal component analysis (PCA). We discuss tropical PCA as a tropical polytope which minimizes the sum of residuals over a tree space. We then apply this to several empirical datasets.

Thursday, Nov. 7

Responding to Students' Mathematical Thinking During Collaborative Problem Solving presented by Jen Munson, Ph.D., Northwestern University

Time: 4:00 p.m.

Refreshments served at 3:50 p.m.

Abstract: While a great deal of attention has been paid to the ways that math teachers can facilitate productive discussions at the end of a lesson, little research has explored how teachers uncover and respond to student thinking during collaborative problem solving. In this talk, I'll share results from a study that characterized interactions in which teachers go beyond eliciting student thinking in the moment, to responding in ways that nudge student thinking forward.

Thursday, oct. 24

The Structure and Interpretation of Graph Spectral Densities presented by David Bindel, Ph.D., Cornell University

Time: 4:00 p.m.

Refreshments served at 3:50 p.m.

Abstract: In this talk, we analyze graphs via global summaries of eigenvalue distributions and eigenvector behavior. Our approach draws from condensed matter physics, where the idea of local and global densities of states is used to understand the electronic structure of systems. We describe how these densities play a common role in such seemingly disparate topics as spectral geometry, condensed matter physics and the study of centrality measures in graphs. We also discuss algorithms to estimate spectral densities.

Friday, oct. 11

The Role of Productive Struggle in Learning Math presented by Kevin Dykema, Mattawan Schools

2019 Mathematics Alumni Award Recipient

Time: 3:00 p.m.

Refreshments served at 2:50 p.m.

Abstract: In 2014, the National Council of Teachers of Mathematics released 8 research-informed mathematics teaching practices with its publication of Principles to Actions. One of those 8 is supporting productive struggle in learning math, which provides a name to what many have done for years. Kevin will share his journey of learning about and implementing productive struggle through experiences as a middle school classroom teacher, graduate student at WMU, conducting professional development throughout the United States, involvement with Michigan Council of Teachers of Mathematics and the National Council of Teachers of Mathematics as board members.