Two theorems on minimal generally-computable numberings

The paper proves that for any set $A$ that computes a non-computable computably enumerable set, any infinite $A$-computable family has an infinite number of pairwise nonequivalent minimal $A$-computable numberings. It is established that an arbitrary set $A\leqslant_T\emptyset '$ is low if and only if any infinite $A$-computable family with the greatest set under inclusion has an infinite number of pairwise nonequivalent positive $A$-computable numberings.