12. A system comprising: a memory comprising instructions; and one or more computer processors, wherein the instructions, when executed by the one or more computer processors, cause the one or more computer processors to perform operations comprising: identifying a word weight for each word in a corpus based on a relevance of each word; receiving a document that comprises a plurality of sentences; assigning to each word in the plurality of sentences a tag indicative of a part of speech of the word; calculating a topic weight for each sentence based on the tags of the words in the sentence; calculating a sentence weight for each sentence based on a sum of the word weights of the words in the sentence the topic weight for the sentence, and a position weight of the sentence within a paragraph, wherein calculating the sentence weight for each sentence further comprises calculating the position weight for the sentence as a maximum between a first constant and a second constant minus a position of the sentence within the paragraph times a third constant; selecting, the sentence with a highest sentence weight as a title for the document; and causing the title to be presented with the document to a user.
12. A system comprising: a memory comprising instructions; and one or more computer processors, wherein the instructions, when executed by the one or more computer processors, cause the one or more computer processors to perform operations comprising: identifying a word weight for each word in a corpus based on a relevance of each word; receiving a document that comprises a plurality of sentences; assigning to each word in the plurality of sentences a tag indicative of a part of speech of the word; calculating a topic weight for each sentence based on the tags of the words in the sentence; calculating a sentence weight for each sentence based on a sum of the word weights of the words in the sentence the topic weight for the sentence, and a position weight of the sentence within a paragraph, wherein calculating the sentence weight for each sentence further comprises calculating the position weight for the sentence as a maximum between a first constant and a second constant minus a position of the sentence within the paragraph times a third constant; selecting, the sentence with a highest sentence weight as a title for the document; and causing the title to be presented with the document to a user. 13. The system as recited in claim 12 , wherein calculating the sentence weight for each sentence further comprises: calculating the sentence weight as the position weight times a weighted sum of the topic weight and the sum of the word weights of the words in the sentence.