Point in surface plot

[technux]

I have plotted a function of two variables as a 3D surface. The function has two critical points and I would like to be able to insert these points as large dots on the plot, but I havn't been able to figure out how to do this.

Can anyone help me?

 

[Occupant]

Why don't you define them as separate variables and plot them as Plot 2, 3 or whatever then you can assign via the properties window different sizes to them.

 

[technux]

I managed to define them as P1(x,y) and P2(x,y), thank you.