Haefliger’s approach for spherical knots modulo immersions

Abstract

$\def\Emb{\overline{Emb}}$We show that for the spaces of spherical embeddings modulo immersions $\Emb (S^n, S^{n+q})$ and long embeddings modulo immersions $\Emb_\partial (D^n, D^{n+q})$, the set of connected components is isomorphic to $\pi_{n+1} (SG, SG_q)$ for $q \geqslant 3$. As a consequence, we show that all the terms of the long exact sequence of the triad $(SG; SO, SG_q)$ have a geometric meaning relating to spherical embeddings and immersions.