User:Dojarca/test


 * Translation:
 * Differential invariant of affine unimodular group is the quantity $$\kappa = \left| \left( x y - x y \right) \phi^{-5} - \frac{1}{2} (\phi^{-2}) \right| \text{ where } \phi=(x'y-xy')^{1/2}$$, so $$\kappa$$ is the object of affine differential geometry (called affine curvature of the plane curve).