Orbit-Method description of the unitary dual for real reductive groups

Let GRG_{\mathbb{R}} be a real reductive group. Let Πu(GR)\Pi_u(G_{\mathbb{R}}) be the set of equivalence classes of irreducible unitary GRG_{\mathbb{R}}-representations, and let Π0(GR)\Pi_0(G_{\mathbb{R}}) be the corresponding set of birationally rigid unipotent representations. For every Levi subgroup LRL_{\mathbb{R}} of GRG_{\mathbb{R}}, let I(Π0(LR))I(\Pi_0(L_{\mathbb{R}})) denote the representations obtained from these representations by the stated sequence of real parabolic induction, unitarity-preserving cohomological induction, generalized complementary-series constructions, and extraction of direct summands. Orbit-Method conjecture. There is an equality

Πu(GR)=LRGRI(Π0(LR)),\Pi_u(G_{\mathbb{R}})=\bigcup_{L_{\mathbb{R}}\subset G_{\mathbb{R}}}I(\Pi_0(L_{\mathbb{R}})),

where the union runs over all GRG_{\mathbb{R}}-conjugacy classes of Levi subgroups of GRG_{\mathbb{R}}. This conjecturally describes the entire unitary dual by starting with birationally rigid unipotent representations of Levi subgroups and applying the three unitary-preserving procedures. The source leaves the generalized complementary-series construction imprecise and presents the equality as conjectural; no resolution is given.

Sources & referencesView supporting material

Primary source

Dougal Davis and Lucas Mason-Brown, “Hodge theory, intertwining functors, and the Orbit Method for real reductive groups”, arXiv:2503.14794 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.