Star distance and additive constant method

In order to find a geometric representation of a non Euclidian matrix of dissimilarity, the authors study a perturbation of such dissimilarities by addition of a specific distance: the star distance. This technique extends the so-called ‘additive constant method’. In a first step, the authors develop the Torgerson form associated with the perturbed matrix and, in a second step, they give conditions that ensure this form to be positive semi-definite.