nLab
3-morphism

Context

Higher category theory

higher category theory

Basic concepts

Basic theorems

Applications

Models

Morphisms

Functors

Universal constructions

Extra properties and structure

1-categorical presentations


Contents

Definition

A 3-morphism in an n-category is a morphism between 2-morphisms.

Examples

For AA an abelian group, the 3-fold delooping B 3A\mathbf{B}^3 A is a 3-groupoid whose 3-morphisms are given by AA.

Revised on September 11, 2010 10:33:26 by Urs Schreiber (188.20.66.18)