Abstract: A method is disclosed using a digital data processing means for determining from a plurality of candidate words at least one which is both an acceptable spelling and an acceptable inflection of a query word. The words are represented by machine readable coded signals and comprise plural characters. The steps are as follows: Determine a stem portion of such query word. Form a suffix class indication for any one of a plurality of classes in which the query word may be included. Compare the determined query stem with characters in the beginning of such candidate words for finding acceptable and nonacceptable spelling matches. Determine an ending portion, if any, in each individual candidate words which is an acceptable spelling match. Utilize the suffix class indication to select a representation of at least one acceptable suffix for the candidate words.

Abstract: The method uses digital data processing means and stored representations of a table of textual block identifiers for locating in a stored textual data base those textual blocks having the best match with a query. Textual block identifiers each provide an indication of a textual block in a stored data base which contains the corresponding word. The method comprises the following steps: A query word is received having representations of a plurality of words to be located in textual blocks in the stored data base. For each of a plurality of the query words, determine a corresponding set of equivalent words which are contained in the stored data base. Each set of equivalent words is equivalent to the corresponding query word. Each equivalent word has a corresponding group of textual block identifiers represented in the stored table.

Abstract: Digital data processing means employing a method for separating acceptable spellings of words from nonacceptable spellings wherein each word comprises characters assigned positions. The character positions in each word are assigned increasing values from one end of the word to the other, positions of the same number of characters from the same end of each word being assigned the same value. Two words to be compared are called a query word and a candidate word. The method includes the following steps. A representation of a character in a given position of the query word is compared with representations of characters in the next lower position, the same position, and the next higher position in the candidate word and a compare type indication is formed representing a match or a mismatch between each query word character and the candidate word characters under comparison.