Preliminaries

What! You don't know what I'm talking about!!

Let's try a little fraktur $\mathfrak{A B C}$. Let's try a little black board bold $\mathbb{Z, P, Q, R, C}$. Let's try some other symbols like $x \gg 0$ or $\otimes$. How about $M \otimes_{\mathbb{Z}} N$ or ${\mathbb{Z}}^{{\mathbb{Z}}^{\mathbb{Z}}}$?

How about $p \nmid N$ or $\boxplus$?