Sasaki-Einstein 7-Manifolds, Orlik Polynomials and Homology

TL;DR

This paper constructs ten new 7-dimensional Sasaki-Einstein manifolds as links of isolated hypersurface singularities, explicitly determining their third homology groups using Orlik's conjecture and Kähler-Einstein orbifolds.

Contribution

It provides ten explicit examples of 7-dimensional Sasaki-Einstein manifolds with fully determined third homology, expanding known classifications using Orlik's conjecture.

Findings

Ten new 7-dimensional Sasaki-Einstein manifolds constructed.

Third Betti number ranges between 10 and 20.

Explicit homology groups determined for these manifolds.

Abstract

Let $L_f$ be a link of an isolated hypersurface singularity defined by a weighted homogenous polynomial $f.$ In this article, we give ten examples of $2$-connected seven dimensional Sasaki-Einstein manifolds $L_f$ for which $H_{3}(L_f, \mathbb{Z})$ is completely determined. Using the Boyer-Galicki construction of links $L_f$ over particular K\"ahler-Einstein orbifolds, we apply a valid case of Orlik's conjecture to the links $L_f $ so that one is able to explicitly determine $H_{3}(L_f,\mathbb{Z}).$ We give ten such new examples, all of which have the third Betti number satisfy $10\leq b_{3}(L_{f})\leq 20$.