Thus, we impose an inductive bias to guide the learner to correctly associate prepositions with their complements, determiners with corresponding noun phrases, and complementizers with the corresponding relative clauses.
we discourage abstract constituents (i.e., constituents that cannot be grounded in the image) from being combined with a preceding constituent, by modifying the original reward definition (Equation 2) as: where λ is a scalar hyperparameter, v (i) is the image embedding corresponding to the caption being parsed, and abstract denotes the abstractness of the span, defined analogously to concreteness (Equation 1): The intuition here is that the initial heads for prepositional phrases (e.g., on) and relative clauses (e.g., which, where) are usually abstract words.