这个一般读作，而不读作倒三角，或者别的，它是一个算子的符号。

Del so, this guy usually pronounced as del, rather than as pointy triangle going downwards or something like that, it's a symbolic notation for an operator.

youdao

此部分为特别作业范例，为一般阅读作业与随堂问题之外之指定作业。

This section contains examples of homework assignments given in addition to the regularly assigned readings and study questions.

youdao

此部分为特别作业范例，为一般阅读作业与随堂问题之外之指定作业。

This section contains examples of homework assignments given in addition to the regularly assigned readings and study questions.

youdao