advanced ART networks such as TopoART and Hypersphere TopoART that summarise categories to clusters may solve this problem as the shapes of the clusters do not depend on the order of creation of the associated categories. (cf. Fig. 3(g, h) and Fig. 4 of ) References Wasserman, Philip D. (1989), Neural computing: theory and practice, New York: Van Nostrand Reinhold, External links Stephen Grossberg's website ART's implementation for unsupervised learning (ART 1, ART 2A, ART 2A-C and ART distance) Summary of the ART algorithm LibTopoART — TopoART implementations for supervised and unsupervised learning (TopoART, TopoART-AM, TopoART-C, TopoART-R, Episodic TopoART, Hypersphere TopoART, and Hypersphere TopoART-C) Neuropsychology Artificial neural networks