Asymptotic behavior of invariants of syzygies of maximal Cohen-Macaulay modules (2412.05860v1)

Abstract: Let $(A,\mathfrak{m})$ be a complete intersection ring of codimension $c\geq 2$ and dimension $d\geq 1$. Let $M$ be a finitely generated maximal Cohen-Macaulay $A$-module. Set $M_i=\text{Syz}^A_{i}(M)$. Let $e^{\mathfrak{m}}_i(M)$ be the $i$-th Hilbert coefficient of $M$ with respect to $\mathfrak{m}$. We prove for all $i\gg0$, the function $i\mapsto e^{\mathfrak{m}}_j(M_i)$ is a quasi-polynomial type with period $2$ and degree $\text{cx}(M)-1$ for $j=0,1$, where $\text{cx}(M)$ is the complexity of $M.$ For $\text{cx}(M)=2,$ we prove $$\lim_{n\to \infty}\dfrac{e^{\mathfrak{m}}1(M{2n+j})}{n}\geq \lim_{n\to \infty}\dfrac{e^{\mathfrak{m}}0(M{2n+j})}{n}-\lim_{n\to \infty}\dfrac{\mu(M_{2n+j})}{n}$$ for $j=0,1$. When equality holds, we prove that the Castelnuovo-Mumford regularity of the associated graded ring of $M_i$ with respect to the maximal ideal $\mathfrak{m}$ is bounded for all $i\geq 0$.