Maximal classes of Ext-reproduced abelian groups

Ext (.,Z)-reproduced abelian groups are finite

“…This result is derived from the formula Ext (Z p, Z) ~_ Z(p ~) <9 Q~ (notation given below). Although this note relates to the extensive investigations of G~a3E--VttaOEN [1 ], it does not seem that they observed the present main result. An immediate consequence is that Horn (4, Q/Z) ~-A if and only ifA is finite, a result proved by GRossE [2].…”