by Waqas ur Rehman.
Week 13(II):
Lovasz Schrijver Lift and Project system (Guest lecture by Iannis Tourlakis)
Lecture notes by Mathe Stephan.
See also the following surveys
Primal Dual Schema by Goemans and Williamson
Semidefinite Programming and relaxations by
Lovasz
and by Goemans