# Contents

## Idea

The center of an additive category $A$ is the endomorphism ring of the identity functor $Id_A$ (cf. with center).

In general, the center is not functorial, but it is functorial in some important special circumstances, like some reconstruction theorems in the commutative setup. (It is also functorial on equivalences.)

## References

An early occurence of the definition of the center of an additive category is in section 5.d of

Revised on April 8, 2013 21:51:10 by Urs Schreiber (82.113.99.18)