Chernoff Turns 100

HermanChernoff celebrates a milestone today: he turns 100years old. 

We in theoretical computer science know Professor Chernoffprimarily for his ubiquitous Chernoff bounds. The Chernoff bound is an exponentially small upper bound on the tail of arandom variable, in terms of its momentgenerating function.  This bound is particularly useful for the sum ofindependent random variables.   

Many, many results in theoretical computer science useChernoff bounds.  For one set of examples, Chernoff bounds are employed inthe analysis of algorithms such as Quicksort, linear probing inhashing, MinHash, anda randomized algorithm for set balancing.  Foranother example, Chernoff bounds are used to reduce the error probability incomplexity classes such as BPP.  Theseexamples merely scratch the surface of the wide-ranging impact that Chernoffbounds have had. 

Professor Chernoff introduced the Chernoff bound inhis seminalpaper from 1952.  Chernoff credits anotherHerman (Herman Rubin) for the elegant proof of the bound in this paper. Similar bounds had been established earlier by Bernstein andby Cramér. 

In his distinguished career, Chernoff was a professor fordecades at Stanford, MIT, and ultimately Harvard.  In May, Harvard proudlyhosted a symposium inhonor of Professor Chernoff's centenary, which he attended.  The photo above shows him at the symposium, looking as cheerful as ever (photo credit: Professor Sally Thurston). 

Beyond his remarkable research accomplishments,Professor Chernoff has passionately guided an entire generation of exceptionalstatisticians.  According to the MathematicalGenealogy Project, he has advised 26 PhD students, leading to a lineage of288 mathematical descendants.  Chernoff himself earned his PhD at BrownUniversity in 1948 under the supervision of Abraham Wald.  

Professor Chernoff and his wife, Judy Chernoff, havebeen marriedfor more than 75 years.  A BostonTV news story said that the Chernoffs are believed to be the oldestliving couple in Massachusetts.  At the symposium in May, ProfessorChernoff doubted the claim, though he had previously acknowledged that it mightbe true.  Maybe his cherished field of statistics can be used toestimate the likelihood of the claim.   

On this extraordinary milestone day, we extend our heartfeltcongratulations and warmest wishes to Professor Chernoff.  Happy 100thbirthday, Professor Chernoff!  Mazel tov.