Behavior of R -groups for p -adic inner forms of quasi-split special unitary groups

ýWe study R-groups for p-adic inner forms of quasi-split special unitary groupsý. ýWe prove Arthur's conjectureý, ýthe isomorphism between the Knapp-Stein R-group and the Langlands-Arthur R-groupý, ýfor quasi-split special unitary groups and their inner formsý. ýFurthermoreý, ýwe investigate the invariance of the Knapp-Stein R-group within L-packets and between inner formsý. ýThis work is applied to transferring known results in the second-named author's earlier work for quasi-split special unitary groups to their non-quasi-split inner formsý.