• Ph.D., University of Michigan, 1977
  • B.S., University of Oklahoma, 1971


American Mathematical Society, Mathematical Association of America

​Honors and Awards

  • (2006) National Science Foundation Grant DMS-00700193, "Probl​ems on Sieve Methods in Number Theory"
  • (1995) Michigan Section of the MAA Award for Distinguished University Teaching of Mathematics

​Professional Interests

Analytic Number Theory

​​Recent Publications and Presentations

  • (with D. Goldston, J. Pintz, and  C. Yildirim) "Small gaps between primes and almost-primes,'' Trans. Amer. Math. Soc. 36 (2009), 5285-5830.
  • (with D. Goldston, J. Pintz, and  C. Yildirim)  "Small gaps between products of two primes,''  Proceedings of London Mathematical Society, 98 (2009) 741-774.
  • (with G. Kolesnik)  Van der Corput's Method of Exponential Sums, London Mathematical Society Lecture Notes Series 126, Cambridge University Press, Cambridge, 1991.
  • (with C. Ringrose) ``Lower bounds for least quadratic non--residues, "Analytic Number Theory, (edited by B. Berndt, H. Halberstam, H. Diamond, and A. Hildebrand, Birkh\"auser, Boston, 1990) 269-309.
  • An asymptotic estimate related to Selberg's sieve, J. Number Theory, 10 (1978), 83-94.​