sentences:  Skew lattices in rings continue to be a good source of examples and motivation.Skew lattices consisting of exactly two D-classes are called primitive skew lattices.Given such a skew lattice formula_17 with formula_29-classes formula_37 in formula_36, then for any formula_38 and formula_39, the subsets
  
  formula_242{formula_243} formula_244 and formula_245 {formula_246} formula_247
  
  are called, respectively, "cosets of A in B" and "cosets of B in A".