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NORMA is the UNL normalizer. It is expected to normalize knowledge bases, i.e., sets of statements expressed in the UNL KB format. The main goal of the system is to organize and consolidate raw knowledge bases.


Normalization is the process of:

  • suppressing redundancies (relations with the same source and target nodes);
  • suppressing tautologies (relations where the source node is the same as the target node);
  • suppressing contradictions (opposite relations between the same nodes, or the same relations between opposite nodes);
  • generalization (replacing a node by a hyper-node, or a relation by a hyper-relation);
  • specification (replacing a hyper-node by a node or a set of nodes, or a hyper-relation by a relation);
  • merging relations (replacing two nodes by a single node); and
  • dividing relations (replacing one node by two or more nodes).


NORMA has been developed by the Library of Alexandria.