Is anything known about Lovasz Theta Function taking integral value in non-perfect graphs? In particular, does integral value of Lovasz theta always coincide with the size of largest independent set?
For instance, graph below is non-perfect, and its Lovasz theta function gives the independence number.
http://yaroslavvb.com/upload/save/non-perfect.pngIts true for a few other non-perfect graphs I tried, here's a Mathematica package I used to compute it