The features could potentially look at any information in the labels, which are of the form POS, A, η h , η m , L , but in our experiments, we map labels to a pair (GRM( POS, A, η h , η m , L ), A).
the label features are sensitive only to the triple of nonterminals corresponding to the grammatical relation involved in an adjunction, and a binary flag specifiying whether the operation is s-adjunction or r-adjunction.