@techreport{3925, title = "An Algebraic Theory of Complexity for Valued Constraints: Establishing a Galois Connection", author = "David A. Cohen and Paidi Creed and Peter G. Jeavons and Stanislav Zivny", year = "2010", institution = "OUCL", month = "November", number = "RR-10-16", pages = "30", }