theorem Th18: :: PASCAL:18
for a, b, c, d, e, f being Element of F_Real holds
( ( qfconic (a,b,c,d,e,f,|[1,0,0]|) = 0 implies a = 0 ) & ( qfconic (a,b,c,d,e,f,|[0,1,0]|) = 0 implies b = 0 ) & ( qfconic (a,b,c,d,e,f,|[0,0,1]|) = 0 implies c = 0 ) & ( qfconic (0,0,0,d,e,f,|[1,1,1]|) = 0 implies (d + e) + f = 0 ) )