We have used synchrotron x-ray diffraction to study the low-T homoepitaxial growth on Ag(001) and Cu(001) surfaces. For both systems, we found that a large, temperature-dependent vacancy concentration is incorporated in films grown below 160K. The vacancy trapping occurs concomitantly with substantial changes in the surface morphology, where a non-monotonic temperature dependence of the mean-square surface roughness has been previously observed. For Cu/Cu(001) we also found that the concentration of vacancies incorporated at 110K evolves, upon heating, according to the vacancy annealing behavior well-known from radiation damage studies of bulk copper and it is consistent with the activation energy for vacancy mobility.

Each semiprime ring admits a unique projectable, strongly projectable, laterally complete and orthocomplete hull. Almost all of the theory for X–hulls of lattice-ordered groups in Paul Conrad, “The hulls of representable l-groups and f-rings”, J. Austral. Math. Soc. 16 (1973), 385–415, has a counterpart for semiprime rings. The proofs of these results will appear elsewhere. They come in a large part directly from the corresponding theory for lattice-ordered groups. There is also a feedback from the rings to the groups.

In his paper “On the structure of ordered real vector spaces” (Publ. Math. Debrecen 4 (1955–56), 334–343), Erdös shows that a totally ordered real vector space of countable dimension is order isomorphic to a lexicographic direct sum of copies of the group of real numbers. Brown, in “Valued vector spaces of countable dimension” (Publ. Math. Debrecen 18 (1971), 149–151), extends the result to a valued vector space of countable dimension and greatly simplifies the proof. In this note it is shown that a finite valued vector lattice of countable dimension is order isomorphic to a direct sum of o–simple totally ordered vector spaces. One obtains as corollaries the result of Erdös and the applications that Brown makes to totally ordered spaces.

We show that each abelian l–group G is a large l–subgroup of a minimal vector lattice V and if G is archimedean then V is unique, in fact, V is the l–subspace of (Gd)^ that is generated by G, where Gd is the divisible hull of G and (Gd)^ is the Dedekind-MacNeille completion of Gd. If G is non-archimedean then V need not be unique, even if G is totally ordered.