My friend Paul Saylor passed away on November 7th.... read more >>

On October 13, the U.S. Supreme Court ruled that the U.S. Census Bureau could stop the 2020 census early. Here is a link to just one of many recent news articles about the census, New York Times.... read more >>

My post a few days ago, Gil Strang and the CR Matrix Factorization, generated a lot of email. Here is the resulting follow-up to that post.... read more >>

My friend Gil Strang is known for his lectures from MIT course 18.06, Linear Algebra, which are available on MIT OpenCourseWare. He is now describing a new approach to the subject with a series of videos, A 2020 Vision of Linear Algebra. This vision is featured in a new book, Linear Algebra for Everyone.... read more >>

Recently, I had email from a student in Italy.... read more >>

I have added this section to my post a few weeks ago about using the SVD to measure partisanship in the United States Senate.... read more >>

Many observers have noted that the United States Senate has become increasingly partisan in recent years. Votes are being made more frequently along strict political party lines. The singular value decomposition, the SVD, of matrices derived from records of roll call votes in the senate can measure this partisanship.... read more >>

I've blogged about this gem from Lothar Collatz (1910-1990) before, but it deserves to be repeated. Especially since it now provides an elegant example of singleton expansion.... read more >>

Alexa tells me that the definition of serendipity is "the occurrence and development of events by chance in a happy or beneficial way."... read more >>

A Mesmerizing AnimationWe are working on a paper about the Kuramoto model of self-synchronizing oscillators. This animation shows the different initial conditions where six oscillators fail to... read more >>