  The aim of this note is to propose a definition of the scientific diversity
and corollarly, a measure of the "interdisciplinarity" of collaborations. With
respect to previous studies, the proposed approach consists of 2 steps : first,
the definition of similarity between journals and second, these similarities
are used to characterize the homogeneity (or, on the contrary the diversity) of
a publication list (that can be for one individual or a team).
