Abstract: A computer implemented method for transforming an inverted index of a collection of documents into a smaller inverted index of documents. The smaller index contains links to all and only to those documents appearing in a subset of the original collection of documents. The method avoids reprocessing the subset to create the smaller inverted index by intersecting each inverted list with the list of document references from the desired subset. If this intersection is empty then the list is removed from the new smaller index, otherwise the list containing only the intersected reference list is included in the new inverted index. The method is also extended to deal with creating multiple smaller inverted indexes and with propagating updates changes in the first collection of documents down into the smaller inverted index or indexes.

Abstract: The invention is directed to a method, computer program product and computer system for creating an index of a subset of data, comprising: a first step of receiving: a set of data; a first index of said set of data; and identifiers of a subset of data of said set; and a second step of creating a second index of said subset of data according to the first index and said identifiers.

Abstract: The invention concerns a computer-implemented method for spell checking, comprising the steps of: providing a user with a user interface adapted for managing files stored on at least one computer; receiving via the user interface a user action involving at least one first word; returning via the user interface at least one second word selected according to: a distance from said at least one second word to said at least one first word; and data of occurrence of said at least one second word in said files. The invention is also directed to a computer program product and computer system allowing for taking steps according to the invention.