The residual spectrum of U(n,n); contribution from Borel subgroups

In this paper we study the residual spectrum of the quasi-split unitary group G=U(n,n) defined over a number field Fý, ýcoming from the Borel subgroupsý, ýL2dis(G(F)∖G(A))Tý. ýDue to lack of information on the local resultsý, ýthat isý, ýthe image of the local intertwining operators of the principal seriesý, ýour results are incompleteý. ýHoweverý, ýwe describe a conjecture on the residual spectrum and prove a certain special case by using the Knapp-Stein R-group of the unitary groupý.