On diminished multiplier ideal and the termination of flips
Donghyeon Kim
TL;DR
The paper addresses termination of flips in the Minimal Model Program by developing diminished multiplier ideals on singular varieties and leveraging a Nadel-type vanishing framework. The authors extend the diminished multiplier ideal theory to klt pairs, establish a valuation-theoretic bridge to log canonical thresholds, and prove a termination result for flips with scaling under the condition $\kappa_{\sigma}(K_X+\Delta)\ge \dim X-1$ with bounded Cartier index. Key contributions include a generalization of diminished multiplier ideals to singular settings, a vanishing theorem, and a termination criterion that connects cohomological invariants to the dynamics of flips. This provides new tools for tackling long-standing questions in birational geometry and has potential to illuminate broader termination phenomena within the MMP.
Abstract
In this paper, we develop a theory of diminished multiplier ideals on singular varieties which was introduced by Hacon, and developed by Lehmann. We prove a result regarding the termination of certain type of flips with scaling of an ample divisor if the Cartier index is bounded, and if $κ_σ(K_X+Δ)\ge \dim X-1$ holds. The proof uses a theory of diminished multiplier ideal.
