Finding singular points of a non-algebraic curve.

[jdinatale]

Let F : \mathbb{R}^2 \rightarrow \mathbb{R}^2 be the map given by F(x, y) := (x^3 - xy, y^3 - xy). What are some singular points?

Well, I know that for an algebraic curve, a point p_0 = (x_0, y_0) is a singular point if F_x(x_0, y_0) = 0 and F_y(x_0, y_0) = 0.

However, this curve is not algebraic, so I'm not sure if that still applies. If it does, then

F_x(x, y) = (3x^2 - y, -y) = (0, 0) and F_y(x, y) = (-x, 3y^2 - x) = (0, 0) at the point p_0 = (0, 0)

Is that the correct way of determining the singular points? Are there any others?

I graphed it in Mathematica.

 

[micromass]

You don't really have a curve here, but rather something like an algebraic surface. Does your text say how singular points are defined in a surface?? There should probably be a determinant condition.