We have discussed the parsing process and how it can be used to extract relationships from text. It can be used for a number of purposes including grammar checking and machine translation of text. There are numerous text relations possible. These include such relationships as father of, near to, and under. They are concerned with how elements of text are related to each other.

Parsing the text will return relationships that exist within the text. These relationships can be used to extract information of interest. We demonstrated a number of techniques using the OpenNLP and Stanford APIs to parse text.

We also explained how the Stanford API can be used to find coreference resolutions within text. This occurs when two or more expressions, such as "he" or "they", refer to the same person.

We concluded with an example of how a parser is used to extract relations from a sentence. These relations were used to extract information to answer simple "who" type queries about U.S. presidents.

In the next chapter, we will investigate how the techniques developed in this and the previous chapters can be used to solve more complicated problems.