1. A system for knowledge representation in a computer that can enable natural language communication with a computer, the system comprising: at least one hardware processor; a database configured to store at least one table, the at least one table configured to store associations between concepts in a text and associated concept identifiers; and a builder interfaced with the database, the builder configured to, when executed by the at least one hardware processor, construct a table that represents knowledge defined by a text, the construction of the table comprising assigning a unique identifier to a concept defined by the text, building a tree comprising a plurality of sub-concepts by breaking the concept into sub-concepts, and joining sub-concepts into higher order sub-concepts until two or more sub-concepts join to form the concept, and storing the concept and plurality of sub-concepts in the at least one table in the database.