1 results
On Hilbert Covariants
-
- Journal:
- Canadian Journal of Mathematics / Volume 66 / Issue 1 / February 2014
- Published online by Cambridge University Press:
- 20 November 2018, pp. 3-30
- Print publication:
- February 2014
-
- Article
-
- You have access
- Export citation
-
Let
$F$ denote a binary form of order 
$d$ over the complex numbers. If 
$r$ is a divisor of $d$, then the Hilbert covariant 
${{H}_{r,\,d}}\,\left( F \right)$ vanishes exactly when $F$ is the perfect power of an order $r$ form. In geometric terms, the coefficients of 
$H$ give defining equations for the image variety 
$X$ of an embedding 
${{\text{P}}^{r}}\,\to \,{{\text{P}}^{d}}$. In this paper we describe a new construction of the Hilbert covariant and simultaneously situate it into a wider class of covariants called the Göttingen covariants, all of which vanish on $X$. We prove that the ideal generated by the coefficients of $H$ defines $X$ as a scheme. Finally, we exhibit a generalisation of the Göttingen covariants to 
$n$-ary forms using the classical Clebsch transfer principle.
