Chen Theorem is a number theory theorem published by China mathematician Chen Jingrun in 1966, and its detailed proof method was published in 1973.

This theorem proves that any large enough even number can be expressed as the sum of the products of a prime number and no more than two prime numbers, which is what we usually call "1+2".

Chen Jingrun and Shao Pinzong's Goldbach Conjecture (Liaoning Education Press) wrote on page 1 18: The "1+2" result of Chen Jingrun's theorem means:

For any big even number, you can always find the prime number P', p ",or P 1, P2, P3, so that at least one of the following two equations holds:

“N = P '+P”(A)

N=P 1+P2*P3 (B)

Of course, it is not excluded that both (a) and (b) are true, such as 62=43+ 19, 62=7+5× 1 1. "