It seems that I got the math wrong in my post a couple of weeks ago about the $1 trillion lawsuit against Oprah Winfrey.  See "Oprah Stole My Poetry, Man Claims In $1 Trillion Lawsuit," Lowering the Bar (Aug. 12, 2009).  The plaintiff did demand $1.2 trillion dollars, as I reported accurately, but I also said that his demand, which was based on his claim that 650 million copies of Oprah's stolen-poetry book had been sold at $20 each, actually should have been for $1.3 trillion.

I recently got an email from a reader, Steve Kass, claiming that this actually comes out to $13 billion, not $1.3 trillion.  I ran a Google search on Steve and found that he had written an article called "Projectional Entropy in Higher Dimensional Shifts of Finite Type," so my first thought was, what does this guy know about math?  But it turns out that this is math, Steve has a Ph.D. in math, and is in fact an associate professor of mathematics and computer science at Drew University in New Jersey.  Given those facts, together with his work on Kac-Moody algebras and infinite-dimensional Lie algebras, I decided I might take his advice and check whether I had multiplied those two numbers together correctly.

I had not.  It should have been $13 billion.

In my defense, only one reader called me out on this, and he's a math professor.  On the other hand, I've now learned (again) the lesson that if you are going to make smart remarks about other people's mistakes, you should try to avoid making the same kind of mistake yourself.

Link: Steve Kass (his blog)
Link: Projectional Entropy in Higher Dimensional Shifts of Finite Type (a PDF)
Link: Superhero Database (suggesting that at least two superheroes have the power of entropy projection, although this might be a different concept)