Re: Research prime's number

Vincenzo Librandi <vincenzo.librandweoz@xxxxxxxx> writes:
Phil Carmody wrote:

If m=a+b, with a,b>0, and p|gcd(a,b),
then p|a and p|b. So p|m. So m is not prime.

I am sorry for arriving late.
Know it.
When m = a+b is prime ?

to listen again.

You asked how to prove:
If A then B.

I showed you:
If not B, then not A


If you don't know how to get from one to the other, then you
are missing some fairly fundamental mathematical tools.
Google for 'contrapositive' for a start.

As you wish ! I don’t polemize.
Excuse me for my language.

I thing:
m=(a+b) is prime, if and so if, a=prime number,
and b=2*h (for h integer >0)

example:
5=3+2; 7=5+2; 13=11+2; and so on
7=3+4; 11=7+4; 17=13+4; and so on
11=5+6; 13=7+6; 17=11+6; and so on
11=3+8; 13=5+8; 19=11+8; and so on
============================

Respectful
Vincenzo Librandi
vincenzo.librandweoz@xxxxxxxx
.

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