There are various methods to decompose coloured graphs. Decompositions of combinatorial and algebraic structures are special cases of the divide-and-conquer method, where a large problem is partitioned into smaller ones, and a method is given to link solutions of the subproblems to a solution of the original one. The clan decomposition (modular or substitution decomposition), is a structural result on general graphs related to the decomposition by quotients in algebra. | The lectures are divided into a `static' and 'dynamic' parts. The static part is concerned with the decomposability and primitivity. The key notion is that of a clan - a subset of vertices that cannot be distinguished from each other by the outsiders. The `dynamic' part studies the local transformation of switching. The set of labels of the edges is given a group structure. In this way one obtains switching classes of graphs. |

## Lectures |
## Exercises |

**
**

**
**

See also my links for graph theory