如果了包含了所讨论的所有元素,则称之为全集。
universal set of technology, make precision machine tool spindle use Angle contact ball bearing realized either way matching use.万能组配技术,使精密机床主轴用角接触球轴承实现了任意方式的配对使用。
The universal set seemed extremely natural and obvious, yet ultimately several paradoxes of set theory were traced to the assumption that it existed, which mathematicians now know is flawed.全集看起来非常自然和显然,但是最终集合理论的几个矛盾可以追溯到存在全集这个假设,现在数学家们知道而这个假设是有缺陷的。