English

Multiplicity formula for restriction of representations of $\widetilde{{\rm GL}}_{2}(E)$ to $\widetilde{{\rm SL}}_{2}(E)$

Representation Theory 2014-05-26 v1

Abstract

In this note we prove a certain multiplicity formula regarding the restriction of an irreducible admissible genuine representation of a 2-fold cover GL~2(E)\widetilde{{\rm GL}}_{2}(E) of GL2(E){\rm GL}_{2}(E) to the 2-fold cover SL~2(E)\widetilde{{\rm SL}}_{2}(E) of SL2(E){\rm SL}_{2}(E), and find in particular that this multiplicity may not be one, a result that seems to have been noticed before. The proofs follow the standard path via Waldspurger's analysis of theta correspondence between SL~2(E)\widetilde{{\rm SL}}_{2}(E) and PGL2(E){\rm PGL}_{2}(E).

Keywords

Cite

@article{arxiv.1405.6023,
  title  = {Multiplicity formula for restriction of representations of $\widetilde{{\rm GL}}_{2}(E)$ to $\widetilde{{\rm SL}}_{2}(E)$},
  author = {Shiv Prakash Patel and Dipendra Prasad},
  journal= {arXiv preprint arXiv:1405.6023},
  year   = {2014}
}