Whitney Umbrella is the surface of this equation: “x^2-y^2*z == 0”. Note that the z-axis is part of the surface.
The parametric form without the z-handle is: {u*v, u, v^2}
umbrella_eq.gcf
umbrella_para.gcf
whitney_umbrella.nb.zip
✻ ✻ ✻
Whitney umbrella
