闭子集 (bìzǐjí): closed subset (mathematics, top…

Measure Word

一个闭子集 gè

Meanings

1 closed subset (mathematics, topology)

Characters

Examples

HSK 7-9

实数轴上的闭区间是一个闭子集。

Shíshù zhóu shàng de bìqūjiān shì yī gè bìzǐjí.

A closed interval on the real number line is a closed subset.

HSK 7-9

拓扑空间中，闭子集的任意交集仍是闭子集。

Tuòpū kōngjiān zhōng, bìzǐjí de rènyì jiāojí réng shì bìzǐjí.

In a topological space, the arbitrary intersection of closed subsets is still a closed subset.

Tips

usage

Math jargon: 闭 'closed' + 子集 'subset'. The opposite is 开子集 ('open subset'). A subset is 'closed' if it contains all its limit points.

Stroke Order

闭 bì

子 zǐ

集 jí

Related Words

闭集 bìjí

closed set (mathematics, topology)

真子集 zhēnzǐjí

proper subset (mathematics)

闭包 bìbāo

closure (mathematics) - the smallest closed set containing a given set / closure (computer science) - a function bundled together with references to its surrounding state

闭区间 bìqūjiān

closed interval (mathematics)

集合 jíhé HSK 4 #3,792

to gather; to assemble / set (in mathematics)

封闭 fēngbì HSK 4 #5,678

to close off / to seal / closed / isolated

鼻子 bízi HSK 5 #1,891

nose

闭门造车 bìmén-zàochē

to build a cart behind closed doors / to work in isolation, out of touch with reality

闭口 bìkǒu

closed comedone (skincare) / small skin-colored bump under the skin, whitehead

闭 bì HSK 6 #431

to close; to shut / to obstruct; to block