Biordered Sets of Regular Rings

The set of idempotents of a regular semigroup is given an abstract characterization as a regular biordered set in [2], and in [4] it is shown how a biordered set can be associated with a complemented modular lattice. Von Neumann has shown earlier that any complemented modular lattice of order greater than 3 can be realized as the lattice of principal right ideals of a regular ring (see [3]). Here we try to connect these ideas to get a characterization of the biordered sets of a class of regular rings.