sentences:  A skew lattice is a set "S" equipped with two associative, idempotent binary operations formula_1 and formula_2, called "meet" and "join", that validate the following dual pair of absorption laws
  
  formula_3,
  
  formula_4.Given that formula_5 and formula_6 are associative and idempotent, these identities are equivalent to validating the following dual pair of statements