摘要
In [1], C. C. Chang defined the class of sets constructible using L<sub>ω|ω|</sub>, and discussed some properties of C in ZFC. However, in ZF, we cannot prove that C satisfies the axiom of choice (AC). In this note, we shall develop an axiomatic system ZFC<sup>*</sup> in which we are able to prove that C satisfies AC.