# Add empty point in an Epilog of a plot

I'm attempting to plot a phase plot for a 1d dynamical system, and mark the stable and unstable fixed point in empty and full point face color, but find it extremely difficult.

Can anyone pointout how to plot in the most simplified way empty and full circles in the same plot?

here is the code

    aa = 1.5;
f[x_] := a x - x^3;
Show[{Plot[f[x] /. a -> aa, {x, -2, 2},

Ticks -> {{{-Sqrt[a] /. a -> aa, "-\!$$\*SqrtBox[\(a$$]\)"}, {0,
0}, {Sqrt[a] /. a -> aa, "\!$$\*SqrtBox[\(a$$]\)"}}, {{0,
0.1}}}, AxesLabel -> {"x", "f(x)"},
Epilog -> {Black, PointSize@Large, Point[{0, 0}]}],
VectorPlot[{a x - x^3 /. a -> aa, y}, {x, -2, 2}, {y, -0.1, 0.1},
VectorPoints -> Table[{x, 0}, {x, -1.6, 1.6, 0.2}],
VectorScale -> Large]}]

• Perhaps use something like Inset["○", {1, 0}] or Inset["◦", {1, 0}] for your empty points? – J. M. will be back soon Mar 31 '19 at 9:31
• How about Epilog -> {Annulus[{0, 0}, {0.45, 0.5}]} – xin pei Mar 31 '19 at 11:51
• – C. E. Mar 31 '19 at 15:46

We can do what I did in my answer to the question Transcritical Bifurcation phase portraits, which was to use Inset:

unstable = {White, Disk[], Black, Thick, Circle[]};
Plot[
1.5 x - x^3,
{x, -2, 2},
Epilog -> Inset[
Graphics[unstable],
{0, 0},
{0, 0},
Scaled[{0.05, 0.05}]
]] In my other answer, I'm also showing how to draw stable and half-stable markers.

• Also unstable = {White, EdgeForm[Directive[Thick, Black]], Disk[]} – Michael E2 Mar 31 '19 at 17:46
• My only problem with this solution is that the face color of the circle is not transparent – jarhead Apr 1 '19 at 9:45
• @jarhead It shouldn't be too difficult to figure out how to change that, just look at the graphics directive {White, Disk[], Black, Thick, Circle[]} and take a guess at what you need to do in order to remove the white. – C. E. Apr 1 '19 at 9:49