Substitutional dynamical systems, Bratteli diagrams and dimension groups
  The present paper explores substitution minimal systems and their relation to stationary Bratteli diagrams and stationary dimension groups. The constructions involved are algorithmic and explicit, and render an effective method to compute an invariant of (ordered) $K$-theoretic nature for these systems. This new invariant is independent of spectral invariants which have previously been extensively studied. Before we state the main results we give some background. 
Fabien Durand (LAMFA), Bernard Host (LAMA), Christian Skau