If doesn't exist or is NULL, return.

如果不存在或者是NULL，就返回。

youdao

Therefore, it is null.

因此，它是空的。

youdao

If doesn't exist or is NULL, set to and return.

如果不存在或者是NULL，就把设置为并返回。

youdao

So that vector is called a "Null vector."

这种矢量就叫做"零矢量"

耶鲁公开课 - 基础物理课程节选

"The ruling is null and void because it violated the legal procedures and for failing to provide the defence team with sufficient guarantees, " he said.

BBC: Kuwait opposition leader jailed for emir insult

Unless licensed or authorized pursuant to this order, or Executive Order 13159 of June 21, 2000, any attachment, judgment, decree, lien, execution, garnishment, or other judicial process is null and void with respect to any property or interest in property blocked pursuant to this order.

WHITEHOUSE: Executive Order--Russian Highly Enriched Uranium

Yet four years later, here is Wexler, Obama's surrogate, advocating a policy of unilateral abrogation of Israeli sovereignty over 4.5% of its national territory in order to enable the eventual implementation of an offer that was predicated on the notion that "nothing is agreed to until everything is agreed to" and as such is null and void.

CENTERFORSECURITYPOLICY: Fool me twice