Metrics on the multirubric lattice of a rubricator tree

The order Hamming distance on multirubric lattice of a weighed rubricator tree is introduced. Rubricator trees are useful for representation of hierarchical thematic classifiers in the field of organization and search for textual information. The rubricator tree is a root tree where any inner vertex has at least two sons. Any multirubric of a rubricator tree is an antichain of vertices not containing a complete set of sons of any vertex of the tree. The set of all multirubrics of a rubricator tree forms the lattice with the natural dominance relation. Based on the dominance relation, and lattice operations in the multirubric lattice are constructed effective algorithms for calculation the order Hamming distance for the case of an additively weighed rubricator tree. Distances on the multirubrics lattice are suggested to be applied for thematically indexed text information search mechanism as a measure of relevance.