1. A method for generating a summary of a document, the method comprising: extracting, by one or more computer processors, text content from the document; parsing, by one or more computer processors, the text content into a plurality of sentences; parsing, by one or more computer processors, each sentence of the plurality of sentences into a subject and an object; for each sentence of the plurality of sentences, creating, by one or more computer processors, a tuple corresponding to the sentence, the tuple comprising a subject of the sentence and an object of the sentence; receiving, by one or more computer processors, a topic about which to generate the summary; searching, by one or more computer processors, the plurality of created tuples to identify one or more tuples that match the received topic, wherein searching the plurality of created tuples to identify one or more tuples that match the received topic comprises: identifying, by one or more computer processors, a first tuple of the plurality of created tuples that has a subject that matches the topic; identifying, by one or more computer processors, a second tuple of the plurality of created tuples that has an object that matches the topic; identifying, by one or more computer processors, one or more tuples in one or more levels of a first hierarchy, wherein at least one tuple in one level of the first hierarchy has an object that matches the subject of the first tuple, and each tuple in each other level of the first hierarchy has an object that matches a subject of all tuples in another level of the first hierarchy; and identifying, by one or more computer processors, one or more tuples in one or more levels of a second hierarchy, wherein at least one tuple in one level of the second hierarchy has a subject that matches the object of the second tuple, and each tuple in each other level of the second hierarchy has a subject that matches an object of all tuples in another level of the second hierarchy; and generating, by one or more computer processors, a summary of the document comprising the sentences that correspond to the one or more identified tuples that match the topic.