Non-existence of extremal Sasaki metrics via the Berglund-Hübsch transpose

Abstract

We use the Berglund-H\"ubsch transpose rule from classical mirror symmetry in the context of Sasakian geometry and results on relative K-stability in the Sasaki setting developed by Boyer and van Coevering to exhibit examples of Sasaki manifolds of complexity 3 or complexity 4 that do not admit any extremal Sasaki metrics in its whole Sasaki-Reeb cone which is of Gorenstein type. Previously, examples with this feature were produced in by Boyer and van Coevering for Brieskorn-Pham polynomials or their deformations. Our examples are based on the more general framework of invertible polynomials. In particular, we construct families of examples of links with the following property: if the link satisfies the Lichnerowicz obstruction of Gauntlett, Martelli, Sparks and Yau then its Berglund-H\"ubsch dual admits a perturbation in its local moduli, a link arising from a Brieskorn-Pham polynomial, which is obstructed to admitting extremal Sasaki metrics in its whole Sasaki-Reeb cone. Most of the examples produced in this work have the homotopy type of a sphere or are rational homology spheres.