reserve S for with_non_trivial_Instructions COM-Struct;
reserve i,j,k for No-StopCode Instruction of S,
        I,J,K for MacroInstruction of S;

theorem Th13:
 card(i ';' j ';' k) = 4
proof
 thus card(i ';' j ';' k) = card(i ';' j) + 1 by Th11
   .= 3 + 1 by Th12
   .= 4;
end;
