The Web is a rich source of information, but this information is scattered and hidden in the diversity of web pages.
Search engines are windows to the web.
However, the current search engines, designed to identify pages with specified phrases have very limited power. In this paper we present a solution for identifying a set of inter-related information on the web using the duality concept. We propose a solution to this problem that iteratively refines mutually dependent approximations to their identifications. The Digital Library is published by the Association for Computing Machinery.