Unique inclusions of maximal C-clones in maximal clones
  $\mathit{C}$-clones are polymorphism sets of so-called clausal relations, a special type of relations on a finite domain, which first appeared in connection with constraint satisfaction problems in [Creignou et al. 2008]. We completely describe the relationship w.r.t. set inclusion between maximal $\mathit{C}$-clones and maximal clones. As a main result we obtain that for every maximal $\mathit{C}$-clone there exists exactly one maximal clone in which it is contained. A precise description of this unique maximal clone, as well as a corresponding completeness criterion for $\mathit{C}$-clones is given. 
Mike Behrisch and Edith Vargas-Garc\'ia
math.RA