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An intrinsically linked simplicial $n$-complex

Ryo Nikkuni

TL;DR

The paper investigates intrinsic linking phenomena for high-dimensional simplicial complexes embedded in ${\mathbb R}^{2n+1}$ and introduces a new explicit family $K^{(n)}$ built from Type I/II $n$-simplices, showing that every embedding yields a nonsplittable link of an $n$-tetrahedron and an $n$-octahedron with parity $1$ modulo $2$. It extends the toolkit with a higher-dimensional ${\triangle}Y(n)$-exchange and proves a transfer principle that preserves intrinsic linking under these operations, producing many new examples. Collectively, these results generalize classical 3D intrinsic linking (Conway–Gordon–Sachs, Petersen family) to the high-dimensional setting and connect to the van Kampen–Flores non-embeddability, offering a constructive framework for intrinsically linked high-dimensional simplicial complexes.

Abstract

For any positive integer $n$, Lovász-Schrijver, Taniyama and Skopenkov provided examples of simplicial $n$-complexes that inevitably contain a nonsplittable two-component link of $n$-spheres, no matter how they are embedded into the Euclidean $(2n+1)$-space. In this paper, we introduce a new example of such a simplicial $n$-complex through a simple argument in piecewise linear topology and an application of the van Kampen--Flores theorem. Furthermore, we demonstrate the existence of additional such complexes through higher dimensional generalizations of the $\triangle Y$-exchange on graphs.

An intrinsically linked simplicial $n$-complex

TL;DR

The paper investigates intrinsic linking phenomena for high-dimensional simplicial complexes embedded in and introduces a new explicit family built from Type I/II -simplices, showing that every embedding yields a nonsplittable link of an -tetrahedron and an -octahedron with parity modulo . It extends the toolkit with a higher-dimensional -exchange and proves a transfer principle that preserves intrinsic linking under these operations, producing many new examples. Collectively, these results generalize classical 3D intrinsic linking (Conway–Gordon–Sachs, Petersen family) to the high-dimensional setting and connect to the van Kampen–Flores non-embeddability, offering a constructive framework for intrinsically linked high-dimensional simplicial complexes.

Abstract

For any positive integer , Lovász-Schrijver, Taniyama and Skopenkov provided examples of simplicial -complexes that inevitably contain a nonsplittable two-component link of -spheres, no matter how they are embedded into the Euclidean -space. In this paper, we introduce a new example of such a simplicial -complex through a simple argument in piecewise linear topology and an application of the van Kampen--Flores theorem. Furthermore, we demonstrate the existence of additional such complexes through higher dimensional generalizations of the -exchange on graphs.

Paper Structure

This paper contains 3 sections, 9 theorems, 16 equations, 7 figures.

Key Result

Theorem 1.1

(Conway--Gordon CG83, Sachs S84) For any embedding $f$ of the complete graph on six vertices $K_{6}$ into ${\mathbb R}^{3}$, there exists a pair $\lambda$ in $\Lambda^{1}(K_{6})$ such that ${\rm lk}_{2}(f(\lambda))=1$.

Figures (7)

  • Figure 1.1: Petersen family (Each arrow represents a $\triangle Y$-exchange)
  • Figure 1.2: $\triangle Y$-exchange
  • Figure 1.3: $|a_{0}^{0}a_{2}^{1}a_{0}^{n}|$ of Type I and $|ba_{0}^{1}a_{1}^{n}|$ of Type II ($n=2$)
  • Figure 1.4: $K^{(1)}=K_{3,3,1}=P_{7}$
  • Figure 1.5: $n$-tetrahedron, $n$-octahedron ($n=2$)
  • ...and 2 more figures

Theorems & Definitions (18)

  • Theorem 1.1
  • Theorem 1.2
  • Theorem 1.3
  • Remark 1.4
  • Theorem 1.5
  • Theorem 2.1
  • Remark 2.2
  • Lemma 2.3
  • proof
  • proof : Proof of Theorem \ref{['newIL']}
  • ...and 8 more