该字体称为 blackboard bold（黑板粗体），可使用 \mathbb{} 命令打出。 p.s. \mathbb实际上指的是 黑板粗体 (blackboard bold)，在原先的字母基础上多了一些特定的线条，所以有时候也被称为 双线体 (double struck)。 Does anyone know a good resource (preferably pictures) that illustrates a conventional way to write the special sets symbols, i.e.
A Baddie Hub The Ultimate Guide
$\\bbb p$ i am familiar. In the first post of the thread "cardinal number subtraction", cardinal number subtraction there is a symbol for some kind of set which looks like this: Young authors (and some older ones) seem to prefer blackboard bold to plain bold for the standard number systems (and/or they pick it up by osmosis on web sites such as this.
