On the embeddability of skeleta of manifold triangulations
Daisuke Kishimoto, Takahiro Matsushita
TL;DR
The paper introduces a criterion linking the embeddability of a $d$-skeleton to the embeddability of the complement of a submanifold, enabling new positive examples and a constructive framework. It shows that for an $S^p$-bundle over $S^q$, the $(q-1)$-skeleton embeds into $\\mathbb{R}^{p+q}$, and, when $p+q=2d$ with $p<q$, the $d$-skeleton embeds into $\\mathbb{R}^{2d}$. Via connected-sum techniques, infinitely many closed $2d$-manifolds admit triangulations whose $d$-skeleta are embeddable, providing a broad contrast to nonembeddability results tied to Stiefel-Whitney classes. The proofs rely on smooth triangulations, transversality, isotopy extension, and a Schoenflies-type argument for connected sums.
Abstract
We show a criterion for a skeleton of a manifold triangulation being embeddable into Euclidean space in terms of the complement of a submanifold. As an application, we obtain embeddability of a $(q-1)$-skeleton of a triangulation of an $S^p$-bundle over $S^q$ into $\mathbb{R}^{p+q}$.
