Throughout this paper only abelian l-groups will be considered and G will denote an abelian l-group. G is large in the l-group H or H is an essential extension of G if G is an l-subgroup of H and for each l-ideal L ≠ 0 of H we have L ∩ G ≠ 0. A ν-hull of G is a minimal vector lattice that contains G and is an essential extension of G. Each G admits a ν-hull (Conrad (1970)).We shall be interested in the following properties of G.