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