Table 6.

Number of possible positive real roots for q = 3.

G6	G4	G3	G2	G1	G0	range of ${\mathcal{R}}_0$	no. of possible positive real roots
+	+	−	+	*	−	${\mathcal{R}}_0>2$	1,3
+	+	+	+	*	−	$1<{\mathcal{R}}_0\le 2$	1
+	+	+	+	−	+	${\mathcal{R}}_0<1$	0,2
+	+	+	+	+	+		0