Publication date:
Available online 10 July 2017
Source:Advances in Mathematics
Author(s): James Arthur
We shall describe two problems in Beyond Endoscopy, the strategy advanced by Langlands for bringing the trace formula to bear on the general principle of functoriality. One is to be able to apply the Poisson summation formula to the regular elliptic part of the trace formula for a general linear group $\mathrm{GL}(n+1)$. The other is to be able to recognize the spectral contribution of the nontempered discrete spectrum to the resulting geometric expansion.