Coloured graphs representing PL 4-manifolds

Crystallization theory is a representation method for compact PL manifolds by means of a particular class of edge-coloured graphs. The combinatorial nature of this representation allows to elaborate and implement algorithmic procedures for the generation and analysis of catalogues of closed PL n-manifolds. In this paper we discuss the concepts which are involved in these procedures for n=4 and present classification results arising from the study of the initial segment of the catalogue.