This task involves identifying the compositional operations involved
in argument selection. Most annotation schemes to date encoding
propositional or predicative content have focused on the
identification of the predicate type, the argument extent, and the
semantic role (or label) assigned to that argument by the predicate.
In contrast, this task attempts to capture the "compositional history"
of the argument selection relative to the predicate. In particular,
this task attempts to identify the operations of type adjustment
induced by a predicate over its arguments when they do not match its
selectional properties. The task is defined as follows: for each
argument of a predicate, identify whether the entity in that argument
position satisfies the type expected by the predicate. If not, then
one needs to identify how the entity in that position satisfies the
typing expected by the predicate; that is, to identify the source and
target types in a type-shifting (or coercion) operation.
The possible relations between the predicate and a given argument will, for this task, be restricted to selection and coercion. In selection, the argument NP satisfies the typing requirements of the predicate. For example, in the sentence "The child threw the ball", the object NP "the ball" directly satisfies the type expected by the predicate, Physical Object. If this is not the case, then a coercion has occurred. For example, in the sentence "The White House denied this statement.", the type expected in subject position by the predicate is Human, but the surface NP is typed as Location. The task is to identify both the type mismatch and the type shift; namely Location -> Human. Resources and Corpus Development The following methodology will be followed in corpus creation: (1) A set of target predicates will be selected and a sense inventory compiled for each target, (2) A set of sentences will be randomly selected for each predicate, (3) The target predicate will be disambiguated in each sentence, and a semantic type will be associated with each argument position of the predicate; and (4) In cases of coercion, the source and target types for each relevant argument position will be identified. We will perform double annotation and adjudication over the corpus. Evaluation Methodology Precision and recall will be used as evaluation metrics. A scoring
program will be supplied for participants. Two subtasks will be evaluated
separately: (1) identifying the argument type and (2) identifying
the compositional operation (i.e. selection vs. coercion).
This task is part of a larger effort to annotate text with
compositional operations (see Bibliography).
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