Fig. 2

Hierarchical relations between 11 controlled predicate terms. It shows hierarchical relations between 11 exclusive terms that are pre-defined depending on the resolution of direction and sign. Based on the causality of subject and object in a knowledge unit (KU), the predicate of the KU becomes either of ‘undirected link’ or ‘directed link’. Furthermore, if the more detailed information for the sign is available, the KU can have higher-resolution terms such as ‘positive increase’. In such cases that a biological event existing in normal condition is observed to disappear under certain conditions such as a disease, the predicate of this KU can be ‘missing interaction’