We give some new canonical
representations for forms over ℂ. For example, a general binary quartic form can be
written as the square of a quadratic form plus the fourth power of a linear form. A
general cubic form in (x1,…,xn) can be written uniquely as a sum of the cubes of
linear forms ℓij(xi,…,xj), 1 ≤ i ≤ j ≤ n. A general ternary quartic form is the sum of
the square of a quadratic form and three fourth powers of linear forms. The methods
are classical and elementary.
Department of Mathematics and Center
for Advanced Study
University of Illinois at Urbana-Champaign
1409 W. Green Street
327 Altgeld Hall
Urbana, IL 61801-2975
United States