实数集的上确界公理用到了实数集的子集，这是一种二阶逻辑的陈述。

The supremum axiom of the reals refers to subsets of the reals and is therefore a second-order logical statement.

youdao

实数集的上确界公理用到了实数集的子集，这是一种二阶逻辑的陈述。

The supremum axiom of the reals refers to subsets of the reals and is therefore a second-order logical statement.

youdao