Figures 1 through 4
Fig. 1: β
2
= 0.3; β
4
= 0
b
, 0.15
r
, -0.15
g
Fig. 2: β
2
= 0.6; β
4
= 0
b
, 0.15
r
, -0.15
g
Fig. 3: β
2
= -0.3; β
4
= 0
b
, 0.15
r
, -0.15
g
Fig. 4: β
2
= -0.6; β
4
= 0
b
, 0.15
r
, -0.15
g
Notation: In the above figures β
4
= 0
b
, 0.15
r
, -0.15
g
indicates that the
black
line corresponds to β
4
= 0, the
red
line to &beta
4
= 0.15, and the
green
line to β
4
= -0.15 .