We collect pairs of events that occur with 0, 1 or 2 intervening events, similar to what was done in the 1-skip bigrams strategy.
the probabilities must be defined as: 2 ) = C(e 1 , e 2 ) + C(e 2 , e 1 ) e i e j C(e i , e j ) P (e) = C(e) e C(e ) where C(e 1 , e 2 ) is the number of times that the ordered event pair (e 1 , e 2 ) was counted in the training data, and C(e) is the number of times that the event e was counted.