\( \newcommand\D{\mathrm{d}} \newcommand\E{\mathrm{e}} \newcommand\I{\mathrm{i}} \newcommand\bigOh{\mathcal{O}} \newcommand{\cat}[1]{\mathbf{#1}} \newcommand\curl{\vec{\nabla}\times} \newcommand{\CC}{\mathbb{C}} \newcommand{\NN}{\mathbb{N}} \newcommand{\QQ}{\mathbb{Q}} \newcommand{\RR}{\mathbb{R}} \newcommand{\ZZ}{\mathbb{Z}} \)
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Cat - Category of Small Categories

Table of Contents

1. Definition

The category Cat of Small Categories has as its:

Objects
All small categories
Morphisms
All functors between small categories

Some authors also want to discuss the category of all categories

2. Properties

2.1. Cartesian Closed

The category Cat is Cartesian closed, i.e., the exponential objects of Cat are functor categories.

(See Mac Lane, Categories for the Working Mathematician, 2nd ed, Chapter IV, section 6, penultimate paragraph.)

3. References

  • Saunders Mac Lane, Categories for the Working Mathematician. 2nd ed, Springer.

Last Updated 2021-06-01 Tue 10:00.