Injective hulls of certain $S$-systems over a semilattice

C. S. Johnson, F. R. McMorris
1972 Proceedings of the American Mathematical Society  
We construct, in the category of S-systems over a semilattice, the injective hulls of S-systems which are homomorphic images of S-subsystems of S.
doi:10.1090/s0002-9939-1972-0289687-7 fatcat:kljvnal6ovbahhypnye5hfpm7i