1. A method for compressing a corpus of documents stored in a memory of a computer system, comprising the steps of: converting each document in the corpus of documents stored in the memory into a tokenized representation that includes a document symbol table and a document position table; arranging in the memory the document symbol tables of the documents in the corpus of documents into groups of symbol tables with recurring symbols; and computing a collective symbol table for each group of document symbol tables arranged in the memory; said computing step compressing the tokenized representations of the documents stored in the memory by sharing recurring symbols across the documents in the corpus of documents; wherein said computing step hierarchically arranges each computed collective symbol table into a group symbol table, a residual document symbol table, and a residual page symbol table.
4. The method according to claim 1, further comprising the step of rendering a page description language of page images of the documents in the corpus into bitmap images.