In addition, examination of the particular entities contributing to high levels of semantic similarity might also allow us to characterize the notion of "global topic," albeit in a differentiated way.
if we determine not just one semantic distance measure for the sets of entities in two adjacent utterances, but the individual distances for each combination of those entities (as briefly described in note 13), we can determine those entities that are contributing the greatest amount of semantic similarity to the measure and identify a cluster of entities that can be taken to represent a global topic.