Talk:GCD domain

Gauss lemma[edit]

Doesn't the Gauss lemma hold for GCD domains? -- Taku (talk) 03:19, 13 February 2009 (UTC)[reply]

Which Gauss lemma? Product of primitive polys is primitive? Irreducible implies irreducible over field of fractions? Algebraist 03:30, 13 February 2009 (UTC)[reply]

I meant the first one. (I didn't know the second.) -- Taku (talk) 04:19, 13 February 2009 (UTC)[reply]

They're both called Gauss's lemma, according to my lecturer and our article. The first is true for GCD domains, according to the Chapman & Glaz book. The second easily follows from the first, but I don't have a source for that at the moment. Algebraist 16:31, 13 February 2009 (UTC)[reply]

Polynomial ring of GCD domain[edit]

In the reference for the claim that R[X₁,...,X_n] is a GCD-domain if R is a GCD-domain, I can find that R[X₁,X₁^-1] is a GCD-domain if R is a GCD-domain, which is another statement. — Preceding unsigned comment added by 77.248.14.251 (talk) 00:32, 30 January 2016 (UTC)[reply]

The definition[edit]

I'm not happy with the definition given in this article. Say a,b are elements in a domain. It is not a priori clear, why 'unique minimal principal ideal containing (a,b)' should be the same as 'smallest principal ideal containing (a,b)'. The latter is definitely the correct definition, as it is equivalent to the definition of gcd in terms of elements. (A gcd of a and b is an element g that divides both a and b, such that if x divides a and b, then x divides g.)

(I think there are weird counterexamples if one doesn't add an assumption. There could be an infinite descending chain of principal ideals containing (a,b) (all not minimal), there could be a unique minimal principal ideal containing (a,b) and it is not the smallest if it isn't contained in the infinite chain.) --Wandynsky (talk) 09:34, 14 July 2021 (UTC)[reply]