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Go up to Question 5

Solution to Question 5

live(W) <->  
    (exist  Y  exist  Z  W=Y  &  connected_to(Y,Z) &  live(Z))
     or  W=outside.
connected_to(X,Y) <->
    (X=l_1  &  Y=w_0)
     or  (X=w_0  &  Y=w_1  &  up(s_2))
     or  (X=w_0  &  Y=w_2  &  down(s_2)).
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