Projective modules and exotic group presentations

Vendredi 23 avril 2021

Conférencier: Johnny Nicholson, University College London 

Résumé / Abstract: Two presentations for a group G which have the same deficiency are called exotic if the corresponding presentation complexes are not homotopy equivalent. The first examples of exotic presentations were found by Dunwoody and Metzler in the 1970s but, owing to the difficulty of the algebra involved, few other examples have since been found. In this talk, I will discuss a class of finite groups G for which these algebraic difficulties can be largely reduced to a question about projective ZG modules which we resolve. I will also discuss applications to Wall’s D2 problem and the classification of 4-manifolds.

Le lien pour se connecter est: https://uqam.zoom.us/j/98999725241