Steven Kerckhoff
Steven Paul Kerckhoff (born 1952) is a professor of mathematics at Stanford University, who works on hyperbolic 3-manifolds and Teichmüller spaces. He received his Ph.D. in mathematics from Princeton University in 1978, under the direction of William Thurston. Among his most famous results is his resolution of the Nielsen realization problem, a 1932 conjecture by Jakob Nielsen. Along with William J. Floyd, he wrote large parts of Thurston's influential Princeton lecture notes, and he is well known for his work (some of which is joint with Craig Hodgson) in exploring and clarifying Thurston's hyperbolic Dehn surgery. Kerckhoff is one of four academics from Stanford University, along with Gunnar Carlsson, Ralph Cohen, and R. James Milgram, who were instrumental in developing the controversial California Mathematics Academic Content Standards for the State Board of Education.