“Seven shuffles suffice” by Tim Garoni

“Take a new deck of cards, arranged in its natural order. How many times do you need to shuffle the deck (using a standard riffle shuffle) before the deck is random? In a certain well-defined sense, the answer is 7. A beautiful theory of random walks on groups has been developed in the past few decades to address such questions … We will take a random stroll through this theory.”

LunchMaths seminars are fun presentations on maths. They are aimed at undergraduate students and absolutely no prerequisite knowledge is assumed! To subscribe to the LunchMaths mailing list, email norm.do@monash.edu