zero set

例句：

1. 1. The zero set is the set of all elements in a mathematical domain that have no positive or negative value.
   零集是数学域中所有元素组成的集合，其中没有正数或负数。
2. 2.In statistics, a null set is a set of data where every element has the same probability of occurring.
   在统计学中，一个空集是一个数据集中的元素具有相同发生概率的集合。
3. 3. The researcher found that the zero set was not as expected, leading to further investigation.
   研究人员发现零集并不如预期的那样，这导致了进一步的调查。