transitions , depending on whether the backward-looking center of Ui ? 1 is maintained or not in Ui and on whether CB ( Ui ) is also the most highly ranked entity ( CP ) of Ui : Center Continuation ( CON ) : CB ( Ui ) = CB ( Ui ? 1 ) , and CB ( Ui ) is the most highly ranked CF ( CP ) of Ui ( i.e. , CP ( Ui ) = CB ( Ui ) )