The regular algebra of a poset
arXiv:0805.2563
Abstract
Let be a field. We attach to each finite poset a von Neumann regular -algebra in a functorial way. We show that the monoid of isomorphism classes of finitely generated projective -modules is the abelian monoid generated by with the only relations given by whenever in . This extends the class of monoids for which there is a positive solution to the realization problem for von Neumann regular rings.
47 pages. Revised version, to appear in Trans. Amer. Math. Soc