An unrestricted notion of the finite factorization property
Jonathan Du, Felix Gotti
TL;DR
This work introduces and investigates the unrestricted finite factorization property (U-FF), a natural relaxation of the FF property that requires every atomic element to have finitely many factorizations, equivalently making the atomic submonoid an $FFM$. The authors position U-FF between the classical IDF and FF properties, prove that IDF implies U-FF but not vice versa, and analyze the behavior of U-FF under standard ring-theoretic constructions, notably the $D+M$ and polynomial extension frameworks. A key contribution is a precise transfer criterion for the U-FF property along D+M pullbacks, showing dependence on whether the maximal ideal contains irreducibles and on the finiteness of the unit-group quotient $K^ imes/k^ imes$. The paper also establishes that nearly atomic IDF domains are FFs and provides explicit examples where U-FF behaves differently from FF, including a domain with U-FF whose polynomial ring is not U-FF, highlighting the nuanced boundary between atomic and unrestricted arithmetic in integral domains.
Abstract
A nonzero element of an integral domain (or commutative cancellative monoid) is called atomic if it can be written as a finite product of irreducible elements (also called atoms). In this paper, we introduce and investigate an unrestricted version of the finite factorization property, extending the work on unrestricted UFDs carried out by Coykendall and Zafrullah who first studied unrestricted. An integral domain is said to have the unrestricted finite factorization (U-FF) property if every atomic element has only finitely many factorizations, or equivalently, if its atomic subring is a finite factorization domain (FFD). We position the property U-FF within the hierarchy of classical finiteness conditions, showing that every IDF domain is U-FF but not conversely, and we analyze its behavior under standard constructions. In particular, we determine necessary and sufficient conditions for the U-FF property to ascend along $D+M$ extensions, prove that nearly atomic IDF domains are FFDs, and construct an explicit example of an integral domain with the U-FF property whose polynomial ring is not U-FF. These results demonstrate that the U-FF property behaves analogously to the IDF property, while providing a finer interpolation between the IDF and the FF conditions.
