Representation of the projectable and strongly projectable hulls of a lattice-ordered group

Abstract

A representable l-group G can be embedded into a projectable (strongly projectable) l-group; an essential extension of G which is minimal with respect to being projectable (strongly projectable) is unique. In this paper these projectable and strongly projectable “hulls” of G are represented using direct limits. If G is an f-ring, or f-ring without nonzero nilpotent elements, then so are these hulls.