Description: The modern methods of intellectual analysis of data are directed on treatment of large informative arrays with the purpose of finding in them of the hidden conformities to the law. One of widespread forms of presentation of the found dependences are logical rules. Determination of meaningfulness of one or another sign allows to shorten the amount of analysable information and as a result, to shorten the amount of logical terms in the found rules. The offered method of determination of meaningfulness of sign allows to shorten the amount of attributes, participating in description of close great number.
Keywords: logical rules, power of approximation, meaningfulness of sign, fuzzy sets, eventual predicates