Does Z[root(-3)] Qualify as a GCD Domain?

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In summary, the conversation discusses domains and the concept of greatest common divisor (gcd). It mentions that Z[√(-3)] is not a unique factorization domain (UFD) and gives an example of a gcd-domain where gcd(a,b) does not exist. The conversation also discusses the relationship between associates and gcd, and provides an example of two elements in Z[√(-3)] without a gcd.
  • #1
bw0young0math
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Hello. Today I study domains but I have some problems. Please help me.

I learned Z[root(-3)] is not UFD.
Then Z[root(-3)] is a example about gcd-domain( there exist some elts a,b in domain D such that it does not exist gcd(a,b).)

Let a=2, b-1+root(-3) .
a and b are not associates and they just have common divisor 1 and -1.
So gcd(a,b) does not exist.


Hum... I don't know why associate, 1/-1 have some relations with not existing gcd. Please......
 
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  • #2
bw0young0math said:
Hello. Today I study domains but I have some problems. Please help me.

I learned Z[root(-3)] is not UFD.
Then Z[root(-3)] is a example about gcd-domain( there exist some elts a,b in domain D such that it does not exist gcd(a,b).)

Let a=2, b=1+root(-3) . I have changed a "-" to an "=" here. I hope that is what was intended.
a and b are not associates and they just have common divisor 1 and -1.
So gcd(a,b) does not exist.


Hum... I don't know why associate, 1/-1 have some relations with not existing gcd. Please......
There is something wrong here. The only common divisors of a and b are 1 and -1, and that means that a and b do have a gcd, namely 1.

If you want two elements of Z[√(-3)] without a gcd, then I suggest x = 4 and y = -2+2√(-3). Then a and b are both factors of x and of y, because
x = 2*2 = (1+√(-3))(1-√(-3)) and
y = 2(-1+√(-3)) = (1+√(-3))(1+√(-3)).
If x and y had a gcd then it would have to be a multiple of ab = 2+2√(-3). But ab does not divide x or y.
 

FAQ: Does Z[root(-3)] Qualify as a GCD Domain?

What is a GCD-domain in Z[root(-3)]?

A GCD-domain in Z[root(-3)] is a set of elements in the ring Z[root(-3)] that satisfies the following properties: every two elements have a greatest common divisor, every two nonzero elements have a least common multiple, and the distributive property holds for all elements in the domain.

What is the significance of GCD-domains in Z[root(-3)]?

GCD-domains in Z[root(-3)] play an important role in number theory and algebraic geometry. They allow for the study of unique factorization of elements and the existence of common divisors among elements in the domain.

How is a GCD-domain in Z[root(-3)] different from a Euclidean domain?

A GCD-domain in Z[root(-3)] is a special type of ring that has unique factorization and allows for the existence of a greatest common divisor for any two elements. In contrast, a Euclidean domain allows for division with remainder, but does not necessarily have unique factorization or a greatest common divisor for all elements.

Can every element in Z[root(-3)] be written as a unique product of irreducible elements?

Yes, in a GCD-domain in Z[root(-3)], every nonzero element can be factored into a unique product of irreducible elements. This is known as the unique factorization property, which is an important characteristic of GCD-domains.

How can I determine if a ring is a GCD-domain in Z[root(-3)]?

To determine if a ring is a GCD-domain in Z[root(-3)], you can check if it satisfies the properties of a GCD-domain, such as the existence of a greatest common divisor for any two elements and the distributive property. You can also look at specific examples and use the unique factorization property to determine if the ring is a GCD-domain.

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