Proving Goldbach's conjecture by induction (or why it doesn't seem to work)

  • #1
mad mathematician
27
5
Goldbach's claim: every even natural number ##n>4## can be written as a sum of two prime numbers.

Let's call this claim: G(n).
Let's try to solve it by induction.

For n=6=3+3, base check is correct.
Suppose G(n) is correct and let's try to prove that it implies G(n+2) is correct as well. (since if ##n## is even then n+1 is odd and n+2 is obviously even.

So ##n+2=p_1+p_2+2## where both p_i are prime numbers.

Now add ##2## to both sides and we get: ##n+2=p_1+p_2+2##; now both the primes are obviously odd primes (I've excluded 4). I thought of saying that obviously ##p_i+1## are even numbers so if I assume for every even integer k<n we have also G(k), then obviously p_i+1 can be wrriten as a sum of two odd prime numbers. I want to prove the following claim: every sum of four odd primes can be reduced to a sum of two odd primes.

And this would allegdly prove Goldbach's conjecture, but it maybe that this claim is harder to prove...
 
Mathematics news on Phys.org
  • #2
mad mathematician said:
And this would allegdly prove Goldbach's conjecture, but it maybe that this claim is harder to prove...
The sum of four odd primes is even. If Goldbach holds then it is the sum of two primes. Hence, it is a consequence of Goldbach. It does not prove Goldbach. Your "induction step" doubles the number of terms with every step. You need a limitation like Goldbach. Even the known limitations, like "every odd number greater than 1 is the sum of at most five prime numbers" (T.Tao , 2012) do not help here.
 
  • Like
Likes dextercioby
Back
Top