Education
Harvard University; Cornell University.
Harvard University; Cornell University.
His most important contributions have been in recursion theory. Named after him is Sacks forcing, a forcing notion based on perfect sets and the Sacks Density Theorem, which asserts that the partial order of the recursively enumerable Turing degrees is dense. Sacks earned his Doctor of Philosophy in 1961 from Cornell University under the direction of J. Barkley Rosser, with a dissertation entitled On Suborderings of Degrees of Recursive Insolvability.
Among his notable students are Lenore Blum, Harvey Friedman, Sy Friedman, Leo Harrington, Richard Shore, and Theodore Slaman.