P (n j |CF l , s j , A (s j ) = 1) is similar to P (n j |CF l , s j , A(s j ) = 1) and estimated from the frequencies of case slot examples in case frames.
while A (s j ) = 1 means s j is not filled with an overt argument but filled with an antecedent of zero pronoun, case frames are constructed from overt predicate argument pairs.