Tiling the 4-ball with knotted surfaces
James Ross, Hannah Schwartz, Andrew Ye
TL;DR
This work solves a 4D analogue of tiling a cube by congruent knotted objects: for any closed orientable surface $F$ in $\mathbb{R}^4$ and any $n \ge 3$, the unit $4$-ball $B^4$ can be monohedrally tiled by $n$ tiles each congruent to a regular neighborhood of $F$ (with corners). The method combines bridge trisections of Meier–Zupan with a Complement Covering Theorem to decompose $B^4$ into a neighborhood of $F$ and a pair of $4$-balls, then generalizes Oh's 3D tiling construction to four dimensions via a pinwheel-like assembly to obtain arbitrary $n \ge 3$. The results answer Adams's question on higher-dimensional analogues of tilings by knotted tori, extend the 3D tiling framework to $4$-dimensions, and provide a structured approach to tilings by thickened knotted surfaces in $B^4$. This establishes a robust foundation for high-dimensional rep-tiles and tilings involving knotted surfaces, with potential implications for isotopy classifications and geometric decompositions in 4-manifold topology.
Abstract
We show that for any closed, orientable surface $K$ smoothly embedded in $\mathbb{R}^4$, the unit $4$-ball $B^4 \subset \mathbb{R}^4$ can be tiled using $n \geq 3$ tiles each congruent to a regular neighborhood (with corners) of a surface smoothly isotopic to $K$. This gives a 4-dimensional analog of tilings of the $3$-ball that were constructed in the 90's using congruent knotted tori.
