An integral domain R is a unique factorization domain if
- Every nonzero, non-unit r∈R can be written as a product of irreducibles; and
- Whenever p1⋯pn=q1⋯qm for pi,qj irreducible and m,n∈N, then m=n and there is a relabeling/reordering of the qj such that qi is associate to pi for all 1≤i≤n.
In particular, for every association class of irreducibles, we can choose a representative, and let P be the collection of such representatives so that every r∈R can be written uniquely as r=up∈P∏pep for u a unit and all but finitely many of the ep equal to zero.
Wikidata ID: Q1052579