Nam Nguyen wrote: > On 10/08/2013 3:04 PM, Bart Goddard wrote:
>> Indeed. E.g., let p and q be two distinct primes. Use the Euclidean >> algorithm to express their gcd as a linear combination of p and q, >> say, ap + bq =1. > > Where did you learn that, in the natural numbers, ap + bq = 1, given p > and q are 2 primes ?
"in the natural numbers" is your addition.
-- Nam Nguyen in sci.logic in the thread 'Q on incompleteness proof' on 16/07/2013 at 02:16: "there can be such a group where informally it's impossible to know the truth value of the abelian expression Axy[x + y = y + x]".