An open question for $d$-tilting bundles on Geigle-Lenzing projective spaces
Jianmin Chen, Weikang Weng
TL;DR
The paper investigates when a $d$-tilting bundle on a Geigle–Lenzing projective space $\,\mathbb{X}$ lifts to a $d$-tilting object in the corresponding Cohen–Macaulay category $\,\underline{\mathsf{CM}}^{\mathbb{L}} R$. Focusing on $d=2$ and GL type $(2,2,p,q)$, it constructs a 2-tilting bundle $M$ on $\,\mathbb{X}$ via a prescribed combination of CM-tilting summands and line bundles, and proves that $\,\pi(M)$ remains a 2-tilting bundle; the paper also derives exact non-tilting criteria in the CM category for specific $(p,q)$ values and uses $2$-APR mutations to relate different tilting bundles. Two non-examples are provided: one showing the open-question negative in weight type $(2,2,2,4)$, and another demonstrating that the converse of a partial tilting result can fail even when a 2-tilting bundle/object exists. These results illuminate the limitations of lifting tilting structures from the geometric setting to the CM category and highlight the role of mutations in navigating the landscape of $2$-tilting objects on GL spaces.
Abstract
We construct a family of $2$-tilting bundles on a Geigle-Lenzing projective space of type $(2,2,p,q)$ via the action of iterated $2$-APR mutations. As an application, we give some non-examples for an open question raised by Herschend, Iyama, Minamoto and Oppermann in the paper "Representation theory of Geigle-Lenzing complete intersections".
