LOCAL COMPARABILITY OF EXCHANGE IDEALS

Separative Ideals of Exchange Rings

Edge ideals of clique clutters of comparability graphs and the normality of monomial ideals

Let (P,≺) be a finite poset and let G be its comparability graph. If cl(G) is the clutter of maximal cliques of G, we prove that cl(G) satisfies the maxflow min-cut property and that its edge ideal is normally torsion free. We prove that edge ideals of complete admissible uniform clutters are normally torsion free. The normality of a monomial ideal is expressed in terms of blocking polyhedra an...

separative ideals of exchange rings

Elements in Exchange Rings with Related Comparability

We show that if R is an exchange ring, then the following are equivalent: (1) R satisfies related comparability. (2) Given a,b,d ∈ R with aR+bR = dR, there exists a related unit w ∈ R such that a+bt = dw. (3) Given a,b ∈ R with aR = bR, there exists a related unit w ∈ R such that a= bw. Moreover, we investigate the dual problems for rings which are quasi-injective as right modules.

Local Cohomology at Monomial Ideals