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 Th98:
  for z,q,x holds ((((x | x) | q) | ((z | z) | q)) | ((q | (x | z)
) | (q | (x | z)))) = ((((z | z) | (z | z)) | ((x | x) | q)) | ((q | q) | ((x |
  x) | q)))
proof
  let z,q,x;
  (((x | x) | q) | ((z | z) | q)) = ((q | (x | z)) | (q | (x | z))) by
SHEFFER1:def 15;
  hence thesis by SHEFFER1:def 15;
end;
