Sur les anneaux euclidiens
Let be a Krull monoid with finite class group such that every class contains a prime divisor (for example, a ring of integers in an algebraic number field or a holomorphy ring in an algebraic function field). The catenary degree of is the smallest integer with the following property: for each and each two factorizations of , there exist factorizations of such that, for each , arises from by replacing at most atoms from by at most new atoms. Under a very mild condition...
For an order embedding of a partly ordered group into an -group a topology is introduced on which is defined by a family of valuations on . Some density properties of sets , and ( being -ideals in ) in the topological space are then investigated, each of them being equivalent to the statement that is a strong theory of quasi-divisors.
Let be the ring of integer valued polynomials over . This ring is known to be a Prüfer domain. But it seems there does not exist an algorithm for inverting a nonzero finitely generated ideal of . In this note we show how to obtain such an algorithm by deciphering a classical abstract proof that uses localisations of at all prime ideals of . This confirms a general program of deciphering abstract classical proofs in order to obtain algorithmic proofs.
Sia a un intero algebrico con il polinomio minimale . Si danno condizioni necessarie e sufficienti affinché l'anello sia seminormale o -chiuso per mezzo di . Come applicazione, in particolare, si ottiene che se , , le condizioni sono espresse mediante il discriminante de .