Department of Mathematics

Van Vleck Hall, 480 Lincoln Drive, Madison, WI

News Items

Daniel Erman Explains The Josephus Problem on Numberphile

Daniel Erman did a guest video with the youtube series Numberphile about the Josephus problem.  This was one of the first problems he encountered in high school where he didn't know how to approach a complex problem with a wide variability of inputs and solutions.   He talks about an early mentor who encouraged him to spend time experimenting with the inputs and solutions to see if he could find a pattern.  He explains the process to web viewers in a simple and accessible way, much like his early mentor did.   

Check out his video here:

Daniel Erman is also the faculty advisor for the UW Math Circle (, which is an outreach group dedicated to helping younger students interested in math learn more about the many exciting things you can discover by experimenting with numbers.


Brian Street wins Certain/Sandefur award

Congratuations to our own Brian Street, the winner of the Certain/Sandefur award. The Certain/Sandefur award is given to one newly tenured Professor in the College of L&S in recognition of both research and teaching excellence.  Brian stood out among 27 newly promoted and astonishingly impressive Associate Professors.   Congratulations Brian!

Madison Workshop in Analysis and PDE

The Analysis and Applications RTG will be holding a workshop in Analysis and PDE here on October 1-2, 2016. The conference website is available here:  

The format of the conference is something in-between a conference and an autumn school. Each speaker will give 2 talks, one of which will serve as an expository introduction to their research area and should be accessible to first-year graduate students, and one which is based on recent progress in that field. 

Jean-Luc Thiffeault Explores "A More Perfect Taffy"

Jean-Luc Thiffeault recently was featured in the Washington Post's Wonkblog on his paper exploring the mathematical history of taffy pullers.  (Link to paper:  

In the Washington Post article, Thiffeault describes moving from exploring taffy as part of fluid dynamics lectures to exporing where taffy machines came from and how they've evolved to be mathematical models of efficiency in mixing, if only to introduce enough complexity to avoid another's patent.   Thiffeault even thought about how to make his own more efficient model, as evidenced by his prototype for his improved taffy puller.  (Link:  Rest assured, Thiffeault isn't going to ditch his job to make a living pulling taffy, noting "Making candy is really difficult...The process was a revelation into how complicated it is."

Craciun Puts Forth Solution For The Global Attractor Conjecture

The Global Attractor Conjecture (GAC) is one of the oldest and best studied problems within Reaction Network Theory, and is closely related to the Boltzmann equation. Indeed, the most general setting for the GAC can be traced back to Boltzmann's work on the H-theorem in the 1870s.

Since its formulation in the early 1970s, the GAC has resulted in a flurry of research activity, dozens of papers discussing various special cases, and a litany of false proofs. (The result is so intuitive that even Horn and Jackson, the authors of the groundbreaking 1972 paper "General Mass Action Kinetics", errantly believed they had already proved it!)

In his recent manuscript, "Toric Differential Inclusions and a Proof of the Global Attractor Conjecture", Professor Gheorghe Craciun proposed a proof of the conjecture in full generality. The manuscript represents the culmination of nearly a decade of work, and involves ideas from dynamical systems, differential inclusions, polyhedral geometry, and algebraic geometry.

A few years before Gheorghe's work, David Anderson used a different approach to prove an important special case of the conjecture.

A recent SIAM News article discusses Gheorghe's proof and a recent Workshop to examine it further at San Jose State University in March 2016.


Gheorghe will give a Colloquium talk on this work on September 23, 2016.


UW-Madison Department of Mathematics
Van Vleck Hall
480 Lincoln Drive
Madison, Wi  53706

(608) 263-3054

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