# You're reading: Posts Tagged: Persi Diaconis

### Persi Diaconis lecture: “The Magic of Martin Gardner”

The one and only Persi Diaconis is going to give a lecture on Martin Gardner at Queen Mary University of London next April. Exciting!

As part of the 2014 British Mathematical Colloquium, join Professor Persi Diaconis, mathematician and former professional magician to celebrate the centenary of the birth of Martin Gardner, with a lecture on the life, work and magic of this famous populariser of mathematics and science.

Martin Gardner brought mathematics to life for millions of people from homemakers to professional mathematicians. Professor Diaconis will try to explain what he did and how he did it. From Alice in Wonderland, Psychic exposures, bad poetry, the Game of Life, public key cryptography and a thousand other things, his clarity and curiosity are contagious. But, beware–as someone once wrote:

WARNING: Martin Gardner has turned dozens of innocent youngsters into math professors and thousands of math professors into innocent youngsters.

The hour-long lecture will take place at 18:30 on the 7th of April, 2014, in the Great Hall of QMUL’s People’s Palace.

The Magic of Martin Gardner event page at QMUL.

### Cushing your luck: properties of randomly chosen numbers

Long-time Aperiodical muse David Cushing has made a bet with us that he can give us an interesting post every Friday for the next ten weeks. Every week that he sends a post, we buy him a bar of chocolate. Every week that he doesn’t send us a post, he buys us a bar of chocolate. For his first trick, David is going to do some unnatural things with the natural numbers.

The greatest common divisor (gcd) of two or more integers is the greatest integer that evenly divides those integers. For example, the gcd of $8$ and $12$ is $4$ (usually written as $\gcd(8,12)=4$). Two integers are called coprime (or “relatively prime”) if their gcd is equal to $1$.

A reasonable question to ask is,

Given two randomly chosen integers $a$ and $b$, what is the probability that $\gcd(a,b)=1$?

### David’s de Bruijn sequence card trick

A few days ago, my friend David asked me if I could help him with a card trick. I said I could, hence this post. I managed to pin David down in front of my camera long enough for him to demonstrate the trick; a full explanation follows this video:

### The Odds Gods smile on birthday/card matches

The classic birthday problem asks how many people are required to ensure a greater than 50% chance of having at least one birthday match, meaning that two or more people share a birthday. The surprisingly small answer, assuming that all birthdays are equally likely and ignoring leap years like 2012, is 23 people.