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 Th95:
  for w,p holds ((p | p) | (p | (w | (w | w)))) = (((w | w) | p) |
  (((w | w) | (w | w)) | p))
proof
  let w,p;
  p | (w | (w | w)) = p | p by SHEFFER1:def 14;
  hence thesis by SHEFFER1:def 15;
end;
