Stratified Whitehead's theorem and knot invariants

By considering homotopies that preserve the stratification, one obtains a natural notion of homotopy for stratified spaces. In this short note, we introduce invariants of stratified homotopy, the stratified homotopy groups. We show that they satisify a stratified version of Whitehead’s theorem. As an example, we introduce a complete knot invariant defined via the stratified homotopy groups

En consid'erant des homotopies pr'eservant la stratification, on obtient une notion naturelle d’homotopie pour les espaces stratifi'es. Dans cette note, on pr'esente des invariants d’homotopie stratifi'ee, les groupes d’homotopie stratifi'es. On montre que ces groupes d’homotopie stratifi'es v'erifient un analogue stratifi'e au th'eor`eme de Whitehead. Comme illustration, on pr'esente un invariant de noeud complet d'efini `a partir des groupes d’homotopie stratifi'es.