
ALT Top Figure. The histograms illustrate the total number of SEP applications by metropolitan area during the 3G and 4G periods. The y-axis represents the count of all patents that include at least one inventor residing in the area during the specified period. The x-axis displays the top ten EU metropolitan areas ranked by their SEP production for that time frame. Bottom Figure. The x-axis shows the count of all H04 patent applications containing at least one inventor residing in the metropolitan area during the 3G and 4G periods. The y-axis represents the number of SEP applications during the same time frame. The solid line shows the fitted linear regression, and the shaded band around the fitted line denotes the 95 per cent confidence interval of the estimated regression. We also report the corresponding regression estimates in the top left corner.













