## Daniel Ellsberg and the Science of Extortion

I don't believe that responsible people should indulge in anything that can be even remotely considered ultimatums or threats. That is not the way to reach peaceful solutions.—President Eisenhower, July 8, 1959. Daniel Ellsberg and the science of extortion Bill Casselman University of British Columbia Daniel Ellsberg died just lastRead More →

## Hat Tricks

Up until recently, all known aperiodic tilings used a minimum of two shapes, and it has long been a major problem to find a tiling that uses just one. Quite recently this problem has been solved, although only with a qualification… Hat Tricks Bill Casselman University of British Columbia “ButRead More →

## What will they do when quantum computers start working?

Mathematically, the most intriguing of the new proposals use lattices for message encryption… What will they do when quantum computers start working? Bill Casselman University of British Columbia Commercial transactions on the internet are invariably passed through a process that hides them from unauthorized parties, using RSA public key encryptionRead More →

## Wordle is a game of chance

Many of the proposed strategies use the notions introduced by Claude Shannon to solve problems of communication… Wordle is a game of chance William Casselman University of British Columbia The game Wordle, which is found currently on the New York Times official Wordle site, can be played by anybody withRead More →

## An epidemic is a sequence of random events

An epidemic is a sequence of random events If a contact is made, then whether or not infection is transferred is much like tossing a (loaded) coin. How can a simulation take all this uncertainty into account? Bill Casselman University of British Columbia Just recently, I started thinking about makingRead More →

## Am I really uninfected?

Am I really uninfected? COVID-19 and rapid testing What’s new is the appearance of a large number of rapid tests, for both professional and home use. They are relatively inexpensive, more convenient to administer, and capable of returning results quickly… Bill Casselman University of British Columbia, Vancouver, Canada I discussedRead More →

## Does He Have It?

Sensitivity, Specificity, and COVID-19 Testing As every doctor should know, medical tests are rarely 100% accurate. Interpreting them is a matter of probability. And probability, of course, is a matter of mathematics… Bill Casselman University of British Columbia, Vancouver, Canada Well, make up your mind. Does he have it orRead More →

## Mathematics and the Family Tree of SARS-Cov-2

Mathematics and the Family Tree of SARS-Cov-2 It’s a remarkable process and, if it weren’t so dangerous to humanity, would be deserving of admiration. … Bill Casselman University of British Columbia, Vancouver, Canada Introduction There are two major ways in which mathematics has contributed to our understanding of the diseaseRead More →

## More Measles

More Measles In this column, I shall say more about modeling the progress of an epidemic. … Bill Casselman University of British Columbia, Vancouver, Canada Introduction This is the second Feature Column in which I discuss the mathematics involved in the transmission of measles. The first one made a fewRead More →