Persi Diaconis

related topics
{game, team, player}
{math, number, function}
{work, book, publish}
{rate, high, increase}
{theory, work, human}
{school, student, university}
{god, call, give}

City College of New York B.S. (1971)

Persi Warren Diaconis (born January 31, 1945) is an American mathematician and former professional magician. He is the Mary V. Sunseri Professor of Statistics and Mathematics at Stanford University. He is particularly known for tackling mathematical problems involving randomness and randomization, such as coin flipping and shuffling playing cards.


Card shuffling

Professor Diaconis achieved brief national fame when he received a MacArthur Fellowship in 1982, and again in 1992 after the publication (with Dave Bayer) of a paper entitled "Trailing the Dovetail Shuffle to Its Lair" (a term coined by magician Charles Jordan in the early 1900s) which established rigorous results on how many times a deck of playing cards must be riffle shuffled before it can be considered random according to the mathematical measure total variation distance. Diaconis is often cited for the simplified proposition that it takes seven shuffles to randomize a deck. More precisely, Diaconis showed that it takes 5 shuffles before the total variation distance of a 52-card deck begins to drop significantly from the maximum value of 1.0, and 7 shuffles before it drops below 0.5, after which it is reduced by a factor of 2 every shuffle.

Diaconis has coauthored several more recent papers expanding on his 1992 results and relating the problem of shuffling cards to other problems in mathematics.

More recently, some have questioned this result, arguing that the measure of randomness is too demanding, and that six shuffles are enough (Trefethen et al., 2000).[1]

Diaconis and colleagues have published follow-up papers, showing that the separation distance of an ordered blackjack deck (that is, aces on top, followed by 2's, followed by 3's, etc.) drops below .5 after 7 shuffles. Separation distance is an upper bound for variation distance.[2][3]


Diaconis left home at 14[4] to travel with sleight-of-hand legend Dai Vernon, and dropped out of high school, promising himself that he would return one day so that he could learn all of the math necessary to read William Feller's famous two-volume treatise on probability theory, An Introduction to Probability Theory and Its Applications. He returned to school (City College of New York for his undergraduate work graduating in 1971 and then a Ph.D. in Mathematical Statistics from Harvard University in 1974), learned Feller, and became a mathematical probabilist.

Full article ▸

related documents
Contract bridge diagram
1952 Summer Olympics
Lilia Podkopayeva
Tinus Osendarp
1984 Winter Olympics
Frankie Fredericks
Chi Cheng
Luis Oliveira
1952 Winter Olympics
Polideportivo Ejido
Willie Davenport
Carlos Valderrama (footballer)
1928 Winter Olympics
Bill Stealey
Southern League (baseball)
Latvian Gambit
Adams State College
1948 Winter Olympics
Eurovision Song Contest 1959
Kalamazoo Kings
Midwest League
Armin Hary
List of Olympic medalists in athletics (women)
Ski jumping at the 2002 Winter Olympics
Snowboarding at the 2002 Winter Olympics
Ross Powers
Tug of war