At the POS, {HEAD ~ the user} invokes {TAIL ~ the application} and then inputs a biometric trait to the phone 
invokes
At the POS , { HEAD ~ the user } invokes { TAIL ~ the application } and then inputs a biometric trait to the phone
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH