category theory

# Contents

## Idea

The identity functor on a category $C$ is the functor $id_C: C \to C$ that maps each object and morphism of $C$ to itself. The identity functors are the identities for composition of functors in Cat.

Revised on July 2, 2017 09:24:14 by Urs Schreiber (88.77.226.246)