A map $f: K \to \mathbb{R}^d$ of a simplicial complex is an almost embedding if $f(\sigma) \cap f(\tau) = \varnothing$ whenever $\sigma, \tau$ are disjoint simplices of $K$. Fix integers $d,k \geqslant 2$ such that $k+2 \leqslant d \leqslant\frac{3k}2+1$. Assuming that the "preimage of a cycle is a cycle" we prove $\mathbf{NP}$-hardness of the algorithmic problem of recognition of almost embeddability of finite $k$-dimensional complexes in $\mathbb{R}^d$. Assuming that $\mathbf{P} \ne \mathbf{NP}$ (and that the "preimage of a cycle is a cycle") we prove that the embedding obstruction is incomplete for $k$-dimensional complexes in $\mathbb{R}^d$ using configuration spaces. Our proof generalizes the Skopenkov-Tancer proof of this result for $d = \frac{3k}{2} + 1$.
翻译:地图 $f: K\ to \ mathbb{R\\\\ da美元 一个简单复合体的地图 {\ k} 2+1$ 几乎嵌入。 假设“ 一个周期的预设是一个周期 ” 我们证明$\ mathbf{ NP} 美元= 美元中几乎嵌入的有限美元- 维综合体几乎可以嵌入的算法问题的坚硬性。 假设 $\ mathb{ k\ gqsland\ ne\ mathbfNP}$ (“ 一个周期的预设是一个周期 ” 。 我们证明, “ 一个周期的预设是一个周期 周期 ”, 而“ 一个周期的预设值是一个周期 ” 我们用 $k$2 的空格 3\\ k 美元= 美元中普通的SK- 校验结果来证明 $k- sk- squal 3\\ 美元- skregreal registration = squal- squal- squal- squal__ d = sqml=xxxxxxxxxxxxxxx =xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx