A $D$-module approach on the equations of the Rees algebra

Abstract

Let $I\subset R=\mathbb{F}[x_1,x_2]$ be a height two ideal minimally generated by three homogeneous polynomials of the same degree $d$, where $\mathbb{F}$ is a field of characteristic zero. We use the theory of $D$-modules to deduce information about the defining equations of the Rees algebra of $I$. Let $\mathcal{K}$ be the kernel of the canonical map $\alpha :\text{Sym}(I)\to \text{Rees}(I)$ from the symmetric algebra of $I$ onto the Rees algebra of $I$. We prove that $\mathcal{K}$ can be described as the solution set of a system of differential equations, that the whole bigraded structure of $\mathcal{K}$ is characterized by the integral roots of certain $b$-functions, and that certain de Rham cohomology groups can give partial information about $\mathcal{K}$.

to appear in J. Commut. Algebra

Cited by in corpus (3)

• Degree and birationality of multi-graded rational maps
• Degree of rational maps via specialization
• On the defining equations of Rees algebra of a height two perfect ideal using the theory of $D$-modules