Beyond Endoscopy

Beyond Endoscopy is the proposal by Langlands for using the trace formula to attack the Principle of Functoriality. Many of the problems at this (early) stage concern the geometric terms in the trace formula. Most immediate perhaps is to extend...

Decomposing symmetric powers

Bill Casselman
One problem raised recently by Langlands in connection with the trace formula was the decomposition of symmetric powers of irreducible representations of $\mathrm{GL}(2)$. There is a classical formula for this. I shall explain a new version of this...