Semirigid GCD domains II
Abstract
Let D be an integral domain with quotient field K, throughout. Call two elements x,y∈D∖{0}v-coprime if xD∩yD=xyD. Call a nonzero non-unit r of an integral domain D rigid if for all x,y|r we have x|y or y|x. Also, call D semirigid if every nonzero non-unit of D is expressible as a finite product of rigid elements. We show that a semirigid domain D is a GCD domain if and only if D satisfies ∗: product of every pair of non-v-coprime rigid elements is again rigid. Next, call a∈D a valuation element if aV∩D=aD for some valuation ring V with D⊆V⊆K and call D a VFD if every nonzero non-unit of D is a finite product of valuation elements. It turns out that a valuation element is what we call a packed element: a rigid element r all of whose powers are rigid and √rD is a prime ideal. Calling D a semi-packed domain (SPD) if every nonzero non-unit of D is a finite product of packed elements, we study SPDs and explore situations in which a variant of an SPD is a semirigid GCD domain.
Communicated by A. Facchini
Dedicated to the memory of Paul Cohn