 reserve T for Ternary_Boolean_Algebra;
 reserve a,b,c,d,e for Element of T;
 reserve x,y,z for Element of T;

theorem Th36b: :: Theorem 3.6 b)
  Tern (a,b,c) = Tern (b,c,a)
  proof
    Tern (a,b,c) = Tern (a,b,Tern(b,c,b`)) by Th35
         .= Tern (Tern(a,b,b),c,Tern(a,b,b`)) by TDis
         .= Tern (b,c,Tern(a,b,b`)) by TRIDef
         .= Tern (b,c,a) by TRADef;
    hence thesis;
  end;
