The Clustering Problem

Abstract

An obvious strategy you may follow in grouping objects is that objects located on the same shelf are much similar to each other, whilst objects belonging to different shelves are very dissimilar. These groups of objects will be named clusters, understanding that they become classes once we acknowledge their utility and reward them for this by giving them a name. For instance, everybody knows what rice is, since it is a suitable and desirable food all over the world. On the contrary, we have as yet no commonly accepted classification of unsuitable e-mails.