Periodicity of Rauzy Scheme for substitution words
  From Rauzy graph Rauzy Scheme can be obtaining by uniting sequence of vertices of ingoing and outgoing degree 1 by arches. This notion is a tool to describe Rauzy graph behavior. For morphic superword we prove periodicity of Rauzy schemes. This fact has consequence in discrete dynamic systems and logic. This fact is also generalization of fact that quadratic irrationals have periodic chain fractions. 
Alexei Kanel-Belov, Ivan Mitrofanov
math.DS