PageRank is a link analysis algorithm that is used by search engine such as Google Internet that assigns a numerical weighting to every element of a hyperlinked set of documents, like the World Wide Web, with the hope of "measuring" the relative importance held in the set. The algorithm may be applied to any numbr of entities with reciprocal quotations and references. The weight taking a numerical value which assigns to any given element E is also known as the PageRank of E and is denoted by PR(E).
A trademark of Google has the name "PageRank"  and this process has been patented (U.S. Patent 6,285,999 ). Nevertheless, the patent is assigned to the University of Stanford and not to Google. Google has exclusive license rights on the patent from the University of Stanford and the university received 1.8 million shares in Google in exchange for use of the patent; the in the year 2005, shares were sold for $336 million.