On the number of generators of powers of an ideal

Abstract

We study the number of generators of ideals in regular rings and ask the question whether $\mu (I)<\mu (I^2)$ if $I$ is not a principal ideal, where $\mu (J)$ denotes the number of generators of an ideal $J$. We provide lower bounds for the number of generators for the powers of an ideal and also show that the CM-type of $I^2$ is $\ge 3$ if $I$ is a monomial ideal of height $n$ in $K[x_1,\dots ,x_n]$ and $n\ge 3$.