theorem
  S is (R11) (R14) implies a * (b * (a * b)") =*=> 1.S
  proof
    assume
A1: S is (R11) (R14);
    a * (b * (a * b)") ==> a*a" & a*a" ==> 1.S by A1,ThI3;
    hence a * (b * (a * b)") =*=> 1.S by Lem3;
  end;
