Sphères d'homologie rationnelle
Sphères d'homotopie nouées
Splitting obstructions and properties of objects in the Nil categories
We show that the objects of Bass-Farrell categories which represent 0 in the corresponding Nil groups are precisely those which are stably triangular. This extends to Waldhausen's Nil group of the amalgamated free product with index 2 factors. Applications include a description of Cappell's special UNil group and reformulations of those splitting and fibering theorems which use the Nil groups.
Structures différentiables sur les types d'homotopie rationnelle simplement connexes
Submersions sur le cercle