not -holdsAt(B │{B\=light_on},C │{C#=<0}) :-
                                   <ul>
                                     <li> 
                                       not o_c_holdsAt1(B │{B\=light_on},C │{C#=<0}) :-
                                       <ul>
                                         <li> 
                                           0 #>= C.
                                         </li> 
                                     </ul> 
                                     </li> 
         