glyn harman (born 2 november 1956) is a british mathematician working in analytic number theory. one of his major interests is prime number theory. he is best known for results on gaps between primes and the greatest prime factor of "p" + "a", as well as his lower bound for the number of carmichael numbers up to x. his monograph "prime-detecting sieves" (2007) was published by princeton university press. he has also written a book "metric number theory" (1998). as well, he has contributed to the field of diophantine approximation.