Cubic form

Source: Wikipedia, the free encyclopedia.

In

zero set of a cubic form. In the case of a cubic form in three variables, the zero set is a cubic plane curve
.

In (

action on the space of integral binary cubic forms and cubic rings up to isomorphism
.

The classification of real cubic forms is linked to the classification of umbilical points of surfaces. The equivalence classes of such cubics form a three-dimensional real projective space and the subset of parabolic forms define a surface – the umbilic torus.[2]

Examples

Notes

  1. ^ In fact, Pierre Deligne pointed out that the correspondence works over an arbitrary scheme.

References