Equality of analytic and algebraic bicentralizers for amenable groups

Prove that the analytic and algebraic relative bicentralizers coincide for every trace-preserving action of an amenable locally compact group on a tracial inclusion $(M,\tau)\subset(N,\tau)$, namely establish $(M\subset N,\alpha)_{\mathrm{analytic}}=(M\subset N,\alpha)_{\mathrm{algebraic}}$.

Background

The paper introduces two versions of the bicentralizer for a trace-preserving action: an analytic bicentralizer defined through asymptotic commutation with almost invariant unitaries, and an algebraic bicentralizer defined using commutants after amplification by L2(G)L^2(G). It proves the inclusion of the algebraic bicentralizer in the analytic one.

The reverse inclusion is conjectured for amenable groups. The result would generalize the earlier bicentralizer conjecture for actions on a single II_1 factor and would identify the analytic asymptotic formulation with the algebraic operator-algebraic formulation for arbitrary tracial inclusions.

References

We conjecture that they agree for amenable groups and prove triviality of the bicentralizer for strictly outer actions of amenable groups with a compact open subgroup, as well as for free Bogoljubov actions of amenable groups on free Gaussian factors.

The classification of flows on $\mathrm{II}_1$ factors and Connes' bicentralizer problem  (2609.11462 - Houdayer et al., 10 Sep 2026) in Section 2, subsection “The bicentralizer conjecture,” immediately before the theorem labeled Conjecture