# Relations, sets, and logic

```latex
a < b \leq c \neq d \approx e \equiv f
```

```latex
x \in A,\quad y \notin B,\quad A \subseteq B,\quad A \cup B,\quad A \cap B,\quad A \setminus B
```

```latex
\mathbb{N} \subset \mathbb{Z} \subset \mathbb{Q} \subset \mathbb{R} \subset \mathbb{C}
```

```latex
(P \land Q) \Rightarrow R \qquad P \Leftrightarrow Q \qquad \forall x\,\exists y\colon x<y
```