00 In Xu Chi's reportage, China people know the conjectures of Chen Jingrun and Goldbach. So, what is Goldbach conjecture? Goldbach is a German middle school teacher and a famous mathematician. He was born in 1690, and was elected as an academician of Russian Academy of Sciences in 1725. 1742, Goldbach found in his teaching that every even number not less than 6 is the sum of two prime numbers (numbers that can only be divisible by 1 and itself). For example, 6=3+3, 12=5+7 and so on. 1On June 7th, 742, Goldbach wrote to Euler, a great mathematician at that time, and put forward the following conjecture: 00(a) Any even number ≥6 can be expressed as the sum of two prime numbers. 00(b) Any odd number ≥9 can be expressed as the sum of no more than three prime numbers. This is the famous Goldbach conjecture. In his reply to him on June 30th, Euler said that he thought this conjecture was correct, but he could not prove it. Describing such a simple problem, even a top mathematician like Euler can't prove it. This conjecture has attracted the attention of many mathematicians. Since Goldbach put forward this conjecture, many mathematicians have been trying to conquer it, but they have not succeeded. Of course, some people have done some specific verification work, such as: 6 = 3+3, 8 = 3+5, 10 = 5+5 = 3+7, 12 = 5+7,14 = 7+7 = 3+/kloc. Someone checked the even numbers within the 8th power of 33× 10 and greater than 6, and Goldbach conjecture (a) was established. But strict mathematical proof requires the efforts of mathematicians. Since then, this famous mathematical problem has attracted the attention of thousands of mathematicians all over the world. 200 years have passed and no one has proved it. Goldbach conjecture has therefore become an unattainable "pearl" in the crown of mathematics. People's enthusiasm for Goldbach conjecture lasted for more than 200 years. Many mathematicians in the world try their best, but they still can't figure it out.

In the 00' s, people began to approach it. 1920, the Norwegian mathematician Brown used an ancient screening method to prove and conclude that every even number greater than 6 can be expressed as (9+9). This method of narrowing the encirclement is very effective, so scientists gradually reduce the prime factor in each number from (99) until each number is a prime number, thus proving Goldbach's conjecture. At present, the best result is proved by China mathematician Chen Jingrun in 1966, which is called Chen Theorem: "Any sufficiently large even number is the sum of a prime number and a natural number, while the latter is only the product of two prime numbers." This result is often called a big even number and can be expressed as "1+2". Before 00 Chen Jingrun, the problem that even numbers can be expressed as the sum of the products of S prime numbers and T prime numbers ("s+t" for short) progressed as follows: 00 1920, and Norwegian Brown proved "9+9". 00 1924, Latmach of Germany proved "7+7". 00 1932, Esterman proved "6+6". 00 1937, Lacey in Italy successively proved "5+7", "4+9", "3+ 15" and "2+366". 00 1938, Bukit Tiber of the Soviet Union proved "5+5". 00 1940, Bukhitab of the Soviet Union proved "4+4". 00 1948 Hungary's Rini proved "1+C", where c is an infinite integer. 00 1956, China Wang Yuan proved "3+4". 00 1957 China and Wang Yuan proved "3+3" and "2+3". 00 1962 Pan Chengdong of China and Barba of the Soviet Union proved "1+5", and Wang Yuan of China proved "1+4". 00 1965, Buchwitz Taber and vinogradov Jr. of the Soviet Union and Pemberley of Italy proved "1+3". 00 1966, China Chen Jingrun proved "2+ 1". It took 46 years from Brown's proof of 1920 of "9+9" to Chen Jingrun's capture of 1966 of "+2". For more than 40 years since the birth of "Chen Theorem", people's further research on Goldbach's conjecture has been in vain.