Kerodon

Notation 2.2.1.8. Let $\operatorname{\mathcal{C}}$ be a $2$-category. We will generally follow the convention of denoting objects of $\operatorname{\mathcal{C}}$ by capital Roman letters, $1$-morphisms of $\operatorname{\mathcal{C}}$ by lowercase Roman letters, and $2$-morphisms of $\operatorname{\mathcal{C}}$ by lowercase Greek letters. However, we will often violate this convention when discussing specific examples. For instance, when studying the (strict) $2$-category $\mathbf{ Cat }$ of small categories (Example 2.2.0.4), we denote objects using calligraphic letters (such as $\operatorname{\mathcal{C}}$ and $\operatorname{\mathcal{D}}$) and $1$-morphisms using uppercase Roman letters (such as $F$ and $G$).