For a real central arrangement $𝒜$, Salvetti introduced a construction of a finite complex Sal$\left(𝒜\right)$ which is homotopy equivalent to the complement of the complexified arrangement in [Sal87]. For the braid arrangement ${𝒜}_{k-1}$, the Salvetti complex Sal$\left({𝒜}_{k-1}\right)$ serves as a good combinatorial model for the homotopy type of the configuration space $F(ℂ,k)$ of $k$ points in $C$, which is homotopy equivalent to the space $C_2\left(k\right)$ of k little $2$-cubes. Motivated by the importance of little cubes in homotopy theory, especially in the study of...

On construit un contre-exemple de la conjecture suivante : si la cohomologie modulo 2 réduite d'un polyGEM 1-connexe quelconque est de type fini et si elle n'est pas réduite à (0), alors elle contient au moins un élément non nilpotent.