On the canonical volume of 3-folds of general type with $P_{12}\geq 2$

TL;DR

This paper investigates the volume of nonsingular projective 3-folds of general type with a specific pluricanonical section index, establishing a new lower bound for the volume when this index equals 12.

Contribution

It provides a new lower bound for the volume of 3-folds of general type with (V)=12, advancing the classification in cases where the basket possibilities are infinite.

Findings

Established that Vol(V)  rac{31}{48048} for (V)=12

Improved previous volume bounds by Chen and Chen

Contributed to the classification of 3-folds with specific pluricanonical properties

Abstract

Let $V$ be a nonsingular projective 3-fold of general type. When the pluricanonical section index $\delta(V)>12$, Chen-Chen \cite{Chen3} has a complete list of the possibility for the weighted basket ${\mathbb B}(V)$. However the possibility of ${\mathbb B}(V)$ could be infinite in the situation $\delta(V)\leq 12$, which is the main challenge to the classification. In this paper we mainly study the case with $\delta(V)=12$ and show that $Vol(V)\geq \frac{31}{48048}$, which improves the corresponding result of Chen--Chen \cite[Prop. 4.9(5)]{Chen3}.