Mok has defined Arthur packets for quasisplit unitary groups. His definition follows Arthur's work on classical groups and relies on harmonic analysis. For real groups there is an alternative definition of Arthur packets, due to Adams-Barbasch-Vogan. It relies on sheaf-theoretic techniques instead of harmonic analysis. We prove that these two definitions of Arthur packets are equivalent in the case of real quasisplit unitary groups.

Langlands defined L-packets for real reductive groups. In order to refine the local Langlands correspondence, Adams-Barbasch-Vogan combined L-packets over all real forms belonging to an inner class ([ABV]). Using different methods, Kaletha also defines such combined L-packets with a refinement to the local Langlands correspondence ([K1]). We prove that the L-packets of Adams-Barbasch-Vogan and Kaletha are the same and are parameterized identically.