Archive for the ‘computer science’ Category

What Is ASCII?


Disclaimer: I am not a historian. I am just a Computer Science educator who likes reading Wikipedia and printing funny characters. This explanation is a long optional appendix for a programming assignment in my course. ASCII is the American Standard Code for Information Interchange. Developed starting in 1960, it was a way of standardizing means of communication between computers. To explain, […]

Some fantastic things as of late. (Not more fantastic than previously but still not bad.) A puzzle. You have an integer array of length N in memory, indexed from 1 to N. Each of the integers that it contains is between 1 and N-1. By the pigeonhole principle, two entries are the same. If the […]

Did you know this is the last day of CS Education Week? The creators of this event are highly engaged in bringing Computer Science to more high schools — in many states, CS is not given full consideration in the curriculum and this is shocking to me given that children are using computers not much later than […]

Last weekend I attended a conference in Budapest where I saw a nice trick in an unexpected place. (A longer report about the whole trip will appear on the CS Theory Blog.) Wikipedia calls it de Moivre’s martingale and the reason that I liked it is that it somehow gives me some intuition, that I formerly […]

Over the last year or so I became interested in a family of problems related to linear programming. In ordinary linear programming, we are given some collection of linear constraints, say {ai x ≥ bi} for i=1, …, n, and the x represents a d-dimensional variable. A central result in optimization says that there is […]



Last weekend I went to a two-day workshop on combinatorics at the Max Planck Institut für Informatik. The place is sort of a European mecca for computer science, as it hosts a gigantic collection of post-docs and students, but had only one professor up until recently. In the city, nearly every restaurant has a logo […]