On the Discriminant Scheme of Homogeneous Polynomials

In this paper, the discriminant scheme of homogeneous polynomials is studied in two particular cases: the case of a single homogeneous polynomial and the case of a collection of n ? 1 homogeneous polynomials in \({n\geqslant 2}\) variables. In both situations, a normalized discriminant polynomial is defined over an arbitrary commutative ring of coefficients by means of the resultant theory. An extensive formalism for this discriminant is then developed, including many new properties and computational rules. Finally, it is shown that this discriminant polynomial is faithful to the geometry: it is a defining equation of the discriminant scheme over a general coefficient ring k, typically a domain, if \({2\neq 0}\) in k. The case where 2 = 0 in k is also analyzed in detail.