IBN Rings and Orderings on Grothendieck Groups

Let R be a ring with an identity element.R∈IBN means that Rm■Rn implies m=n,R ∈IBN1 means that Rm ■Rn⊕K implies m≥n,and R ∈IBN2 means that Rm■Rm⊕K implies K=0.In this paper we give some characteristic properties of IBN1 and IBN2,with orderings o the Grothendieck groups.In addition,we obtain the following results:（1）If R ∈IBM1 and all finitely generated projective left R-modules are stably free,then the Grothendieck group Ko（R）is a totally ordered abelian group.（2）If the pre-ordering of the Grothendieck group Ko（R）of a ring R is a partial ordering,then R ∈IBM1 or Ko（R）=0.

Computation of K0(RMNS_(θ,h))

Let T=RM NS (θ,φ) and θ=0. We use a complete different technique to obtain the generalize results for K 0(T), i.e., K 0(T/I)K 0(R)K 0(S/NM) and K 0(T/J(T)) K 0(R/J(R))K(S/J(S)).

The Torsion-Freeness of Partially Ordered K0-Groups for a Class of Exchange Rings

A ring R is called orthogonal if for any two idempotents e and f in R, the condition that e and f are orthogonal in R implies the condition that [eR] and [fR] are orthogonal in K0(R)+, i.e., [eR]∧[fR] = 0. In this paper, we shall prove that the K0-group of every orthogonal, IBN2 exchange ring is always torsion-free, which generalizes the main result in [3].