reserve x,y for Real;
reserve a,b,c for Element of Real_Lattice;
reserve p,q,r for Element of Real_Lattice;
reserve A,B for non empty set;
reserve f,g,h for Element of Funcs(A,REAL);
reserve L for non empty LattStr,
        p,q,r for Element of L;
reserve p,q,r for Element of RealFunc_Lattice(A);

theorem
  RealFunc_Lattice(A) is D_Lattice
proof
  p"/\"(q"\/"r) = (p"/\"q)"\/"(p"/\"r) by Th20;
  hence thesis by LATTICES:def 11;
end;
