Resumen de Subgroups of Finite Direct Sums of Z[1/n]
Let C(n) denote the class of subgroups of finite direct sums of Z[1/n] for a positive integer n. There is a category equivalence from the isomorphism at n category of C(n) to the class of n-local torsion-free abelian groups of finite rank. Included are a number of examples and a classification of groups in C(n) with rank < 4 for the case that n is a prime number
