When we write in this paper, we refer to natural logarithm. Let , , and be positive integers, be a prime and be the th prime. To begin with, we prove that there are at least three type integers that satisfy when holds. We consider that is the number of . According to the following Dusart’s inequality
holds for , let be as below.
It is confirmed that holds for . holds for since the first term has a greater divergence velocity than the second term. The following inequalities hold for where and hold.
From the above, it is proved that holds for .
We regard and hold. Let be an odd integer and the product of the elements , , …, . We take account of holds.
Let be a positive integer.
We assume that holds for all where holds after this. Let be a positive integer. We consider the following equation.
By the equation (1),
holds. Let be a positive integer.
Comparing the equations (2) and (3), we find that the second term on the equation (3) is times the one on the equation (2). If holds for all , then it becomes a contradiction since is less than one and if this operation is repeated a finite number of times, then the terms will no longer be integers. Hence, the assumption is false. When holds, holds for at least one .
When holds for some , one of the elements in must be because holds and they cannot be three times or more odd multiples of . From the above, it is proved that there are an infinite number of twin prime numbers since at least one of the numbers , , …, must be a prime number when and hold and the sets of numbers between and can be taken infinitely by increasing . (Q.E.D.)