Almost clean rings and arithmetical rings

It is shown that a commutative Bézout ring R with compact minimal prime spectrum is an elementary divisor ring if and only if so is R/L for each minimal prime ideal L. This result is obtained by using the quotient space pSpec R of the prime spectrum of the ring R modulo the equivalence generated by the inclusion. When every prime ideal contains only one minimal prime, for instance if R is arithmetical, pSpec R is Hausdorff and there is a bijection between this quotient space and the minimal prime spectrum Min R, which is a homeomorphism if and only if Min R is compact. If x is a closed point of pSpec R, there is a pure ideal A(x) such that x = V (A(x)). If R is almost clean, i.e. each element is the sum of a regular element with an idempotent, it is shown that pSpec R is totally disconnected and, ∀x ∈ pSpec R, R/A(x) is almost clean; the converse holds if every principal ideal is finitely presented. Some questions posed by Facchini and Faith at the second International Fez Conference on Commutative Ring Theory in 1995, are also investigated. If R is a commutative ring for which the ring Q(R/A) of quotients of R/A is an IF-ring for each proper ideal A, it is proved that RP is a strongly discrete valuation ring for each maximal ideal P and R/A is semicoherent for each proper ideal A.