reserve L for satisfying_Sh_1 non empty ShefferStr;
reserve L for satisfying_Sheffer_1 satisfying_Sheffer_2 satisfying_Sheffer_3
  non empty ShefferStr;
reserve v,q,p,w,z,y,x for Element of L;

theorem Th99:
  for q,z,x holds (q | (x | z)) = ((((z | z) | (z | z)) | ((x | x)
  | q)) | ((q | q) | ((x | x) | q)))
proof
  let q,z,x;
  ((((x | x) | q) | ((z | z) | q)) | ((q | (x | z)) | (q | (x | z)))) = (q
  | (x | z)) by Th94;
  hence thesis by Th98;
end;
