On the theta number of powers of cycle graphs
  We give a closed formula for Lovasz theta number of the powers of cycle graphs and of their complements, the circular complete graphs. As a consequence, we establish that the circular chromatic number of a circular perfect graph is computable in polynomial time. We also derive an asymptotic estimate for this theta number. 
Christine Bachoc (IMB), Arnaud P\^echer (INRIA Bordeaux - Sud-Ouest,   LaBRI), Alain Thi\'ery (IMB)
math.CO