fn defining_equation_projective(
        x: &FieldElement<Self::BaseField>,
        y: &FieldElement<Self::BaseField>,
        z: &FieldElement<Self::BaseField>,
    ) -> FieldElement<Self::BaseField> {
        z * Self::b() * y.square() - x.pow(3_u16) - z * Self::a() * x.square() - z.square() * x
    }
Evaluates the equation at the projective point (x, y, z).
Projective equation: zby^2 = x^3 + zax^2 + z^2x
crates/math/src/elliptic_curve/montgomery/traits.rs