What are the most famous examples of PhD advisors in mathematics, younger than their student?
(if possible put the date of birth and/or the difference in age).
The only example I know is Charlie Fefferman and his first student.
Advisor: Fefferman, born April 18, 1949. Year of PhD 1969.
Student: Antonio Córdoba Barba, born January 12, 1949. Year of PhD 1974.
Difference in age: 3 months and change.
Trivia: that is the only example I know also where both father and son studied under the same PhD advisor.