Patent ID: 7392251

Claim:
A computer implemented method for systematically comparing contents of at least two digitally stored documents (Doc 1 , Doc 2 ), which are stored on digital medium and which are loaded by a computer to be compared by a computer, wherein the stored documents (Doc 1 , Doc 2 ) have marked and unmarked areas, wherein initially all the areas are unmarked, comprising the following steps: a) searching for identical and unique roots (Root 1 , Root 2 ) in the unmarked areas of the documents, of which there are at least two, wherein the roots comprise a string of text symbols, being in particular words, word groups or other unambiguous textual formatting functions, and must only occur exactly once in each of the documents, and wherein if a root is not unambiguous it is discarded, and wherein a search for the root is carried out in the first document in order to determine unambiguity, and then a search for the root is carried out in the second document in order to determine its unambiguity; b) if roots have been found, comparing the documents, starting with the roots (Root 1 , Root 2 ), until there is no longer any agreement, wherein the areas (Area 1 , Area 2 ) found in this way are being marked; c) repeating the above steps, starting with a) in a recursion until there are no longer any unique and identical roots or until no longer any found areas can be marked, wherein the marked areas are at first not taken into account in the search for roots and areas; d) wherein a multi-pass method is used, in which after a first pass only one or several areas which are evaluated as being the best are determined, wherein all other areas are released and unmarked again and subsequently, at the exclusion of the determined area, are determined by new passes, starting with step a), wherein the information stored by the recursion are used.