A lifting principle for canonical stability indices of varieties of general type

TL;DR

This paper establishes a lifting principle for the canonical stability indices of varieties of general type, linking the indices of n-folds to those of (n+1)-folds with large canonical volume, advancing understanding of pluricanonical maps.

Contribution

It proves the lifting principle for canonical stability indices, connecting the indices across dimensions via large canonical volumes, a novel insight in algebraic geometry.

Findings

r_n equals the maximum of stability indices of (n+1)-folds with large volume

Existence of a constant (n) ensuring birationality of pluricanonical maps for volumes above it

Extension of McKernan's lifting principle to a broader class of varieties

Abstract

For any integer $n>0$, the $n$th canonical stability index $r_n$ is defined to be the smallest positive integer so that the $r_n$-canonical map $\Phi_{r_n}$ is stably birational onto its image for all smooth projective $n$-folds of general type. We prove the lifting principle for $\{r_n\}$ as follows: $r_n$ equals to the maximum of the set of those canonical stability indices of smooth projective $(n+1)$-folds with sufficiently large canonical volumes. Equivalently, there exists a constant $\mathfrak{V}(n)>0$ such that, for any smooth projective $n$-fold $X$ with the canonical volume $\textrm{vol}(X)>{\mathfrak V}(n)$, the pluricanonical map $\varphi_{m,X}$ is birational onto the image for all $m\geq r_{n-1}$. The ''lifting principle'' was first put forward by James McKernan in Mathematics Review (MR2339333).