05/13/22: The Generalized Star Height Problem with Jean-Eric Pin

Roughly four years ago, when I took second semester Abstract Algebra at the University of Arizona, my professor (Jay Taylor) generously offered to meet with me every week outside class to discuss algebraic topics in computer science.  We chose Dr. Pin's book, Varieties of Formal Languages.  Due to my own mathematical immaturity we worked through the material slowly, and didn't finish the text before I graduated.  Nevertheless, working through this material helped inspire me to pursue a PhD in formal methods - an endeavor I'm solidly halfway through at the time of writing.  All this is to say, Jean-Eric Pin is partially to blame for the fact that I am currently a sleepless PhD student at Northeastern University.   Today Jean-Eric Pin joined us to discuss The Generalized Star Height Problem, an open problem in formal language theory which he and his colleagues have attempted to attack from all angles: algebraically, logically, topologically, etc.  It's one of those deeply enticing problems in math that's reasonably easy to explain yet apparently quite challenging to solve.  In this 2-hour talk, Jean-Eric Pin explains the problem starting with the most basic definitions, and then discusses some of the related results from those who wish to solve it.  It's a fascinating and very accessible talk, and we really hope you enjoy! You can view a video version of the talk HERE.