The underlying idea is that, for example, in the case of a survey paper, it is natural that publications within the set A and also within the set B will be spread quite far from each other. However, this is not a sign of the paper’s contribution, but rather a natural feature of a survey paper. On the other hand, we believe that if a paper uses ideas from a narrow field, but has an impact on a very large field, it is a sign of the paper’s contribution.