Degree Bounds for a Minimal Markov Basis for the Three-State Toric   Homogeneous Markov Chain Model
  We study the three state toric homogeneous Markov chain model and three special cases of it, namely: (i) when the initial state parameters are constant, (ii) without self-loops, and (iii) when both cases are satisfied at the same time. Using as a key tool a directed multigraph associated to the model, the state-graph, we give a bound on the number of vertices of the polytope associated to the model which does not depend on the time. Based on our computations, we also conjecture the stabilization of the f-vector of the polytope, analyze the normality of the semigroup, give conjectural bounds on the degree of the Markov bases. 
David Haws, Abraham Martin Del Campo, Ruriko Yoshida
math.CO math.ST stat.TH