  We introduce the spectral influence and spectral cyclicality based on the
largest eigenvalue of a graph adjacency matrix, two novel concepts of
centrality capturing diffusion and interdependence from a local and a global
point of view respectively. We define a new clustering algorithm to distinguish
communities with high cyclicality and interdependence, allowing overlapping,
and we conclude our study with an application to the input-output analysis in
the case of the Moroccan economy.
