We don't want deontic may to be confused with other types of modal may , because these other types do not express the same linguistic choice. This problem is related to issues arising from the annotation . You cannot count the same thing twice. The problem arises because a corpus is not like a regular database and 'cases' interact with one another. We have listed these from the most grammatically explicit to the most incidental.
Matches fully overlap one another.
The only aspect of this matching that can be said to be independent is that different nodes refer to different parts of the same tree. If you avoid using unordered relationships in FTFs, this will not happen. Matches partially overlap one another, i.e., part of one FTF coincides with part of another. One match can dominate, or subsume another, for example, a clause within a clause. Alternatively a match might be related to another via a simple construction, e.g., co-ordination.