The model can be used to handle both tree structured semantic representations and lambda calculus expressions, and assumes there exist CCG derivations as joint representations in which each semantic unit is associated with a contiguous word sequence where overlappings amongst word sequences are not allowed.
in practice, we define features at each level of the relaxed hybrid tree structure h. features are defined over (n, m) tuples where n is a contiguous sequence of natural language words (immediately or remotely) associated with the semantic unit m (recall that h contains both n and m, and each level of h simply consists of a semantic unit and a contiguous sequence of words).