The discussion focuses on identifying the various factors of the expression 4ab. Participants list factors such as 4, ab, a, 4b, b, 4a, 2, 2ab, 2b, and 2a. The inclusion of 1 as a factor is confirmed, emphasizing that if a and b are primes, all listed factors are positive integers. The conversation highlights the importance of considering prime variables in factorization. Overall, the thread effectively clarifies the complete set of factors for 4ab.