Séminaires

In 1996 Gilles Carron introduced the notion of nonparabolic operators at infinity and showed that such operators are Fredholm in the usual sense. The question that we could ask ourselves is: can we extend the notion of Carron to $\Gamma$-operators on Galois coverings and still have a notion of Fredholmness upstairs ?

In this talk we will first introduce the notion of an $\mathcal{N}\Gamma$-Hilbert space as introduced by Wolfgang Lück in 1997. Then, we will introduce the notion of $\Gamma$-Fredholm operators defined between $\mathcal{N}\Gamma$-Hilbert spaces. And finally, the goal of the presentation is to define nonparabolic $\Gamma$-near infinity operators and show how they induce $\Gamma$-Fredholmness on admissible domains.