{TAIL ~ The system} of equations and is equivalent to {HEAD ~ the system} of equations , and with respect to the factor L: 
{ TAIL ~ The system } of equations and is equivalent to { HEAD ~ the system } of equations , and with respect to the factor L :
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH