1, Fermat's last theorem

Fermat's Last Theorem, also known as Fermat's Last Theorem, was put forward by French mathematician Pierre de Fermat in the 7th century.

Content: when the integer n > 2, the equation x about x, y and z? + y？ = z？ There is no positive integer solution.

2. Four-color problem

Four-color problem, also known as four-color conjecture and four-color theorem, is one of the three major mathematical problems in the modern world. The four-color theorem of maps was first put forward by a British college student named Goodrich.

Content of the four-color problem: Any map with only four colors can make countries with the same border have different colors. In other words, a map only needs four colors to mark it, which will not cause confusion.

Expressed in mathematical language: divide the plane into non-overlapping areas at will, and each area can always be marked with one of the four numbers 1234, without making two adjacent areas get the same number.

3. Goldbach conjecture

1742 On June 7th, Goldbach put forward the famous Goldbach conjecture.

Content: take any odd number, such as 77, which can be written as the sum of three prime numbers, that is, 77 = 53+17+7; Any odd number, such as 46 1, can be expressed as 46 1=449+7+5, which is also the sum of three prime numbers. 46 1 can also be written as 257+ 199+5, which is still the sum of three prime numbers. There are many examples, that is, it is found that "any odd number greater than 5 is the sum of three prime numbers."