2. The method of claim 1 , further comprising: obtaining a search query; generating a semantic query key term including at least one semantic query token representing a semantic relationship derived from the search query; querying the inverted index with the semantic query key term; and receiving a set of references to information passages associated with the semantic query key term that corresponds to the semantic index key term indexed by the inverted index.
3. The method of claim 2 , further comprising: obtaining a semantic representation of the information passage, the semantic representation of the information passage comprising one or more semantic the substructures, each semantic substructure comprising at least one predicate-argument relation; generating the semantic index token from at least one of the semantic substructures; and generating the semantic index key term including the semantic index token.