The problem with the original MOLT kernel is that it treats subtrees with one mark, i.e., those including only the argument or the predicate node, and subtrees with two marks, i.e., those including both the argument and the predicate nodes equally, although the latter is likely to be more important for distinguishing difficult arguments.
we modified the MOLT kernel so that the marks can be weighted in order to give large weights to the subtrees with many marks.