Discovering Important Chemicals in Lists via Centrality Analysis Networks were constructed for CIDs from the chemical lists. Each (weighted) individual network consisted of the CIDs from a specific list as nodes. An edge connecting a pair of CIDs was established if both CIDs were mentioned by one patent. Each edge was further weighted by the number of co-appearances of the two CIDs in patents. These individual networks resulted in plots (see Figures and ULPatentTrends for examples) that were quite difficult to interpret. More detailed network analysis, shown in Figure (including the US in Figures S9) helped isolate chemicals of particular interest to certain regions.