Unique factorization domain
This article defines a property of integral domains, viz., a property that, given any integral domain, is either true or false for that.
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VIEW RELATED: Commutative unital ring property implications | Commutative unital ring property non-implications |Commutative unital ring metaproperty satisfactions | Commutative unital ring metaproperty dissatisfactions | Commutative unital ring property satisfactions | Commutative unital ring property dissatisfactions
Definition
Symbol-free definition
An integral domain is termed a unique factorization domain or factorial domain if every element can be expressed as a product of finite length of irreducible elements (possibly with multiplicity) in a manner that is unique upto the ordering of the elements.
Definition with symbols
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Relation with other properties
Stronger properties
- Euclidean domain
- Principal ideal domain: For proof of the implication, refer PID implies UFD and for proof of its strictness (i.e. the reverse implication being false) refer UFD not implies PID
Weaker properties
- Normal domain: For full proof, refer: Unique factorization implies normal
- gcd domain: For full proof, refer: UFD implies gcd
- Ring satisfying ACCP
Metaproperties
Polynomial-closedness
This property of integral domains is closed under taking polynomials, i.e., whenever an integral domain has this property, so does the polynomial ring in one variable over it.
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This is essentially what Gauss's lemma states.
Closure under taking localizations
This property of integral domains is closed under taking localizations: the localization at a multiplicatively closed subset of a commutative unital ring with this property, also has this property. In particular, the localization at a prime ideal, and the localization at a maximal ideal, have the property.
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In fact, it is true more generally, that the localization at a multiplicatively closed subset of a unique factorization domain, is a unique factorization domain. Those irreducibles which occur in the saturation of the multiplicatively closed subset that we invert, no longer remain irreducibles; the others continue to remain irreducible.