Tracial quotient of a free product versus free product of tracial quotients
Determine whether, for arbitrary unital separable C*-algebras A1 and A2 with nonempty trace spaces, the tracial quotient of their full free product equals the full free product of their tracial quotients; equivalently, establish whether Atr is canonically ∗-isomorphic to A1,tr ∗ A2,tr for A := A1 ∗ A2.
References
It is not clear to the authors whether for a free product C∗-algebra A = A1 ∗ A2, it is true in general that (⋆) Atr = A1,tr ∗ A2,tr. … We leave it open whether (⋆) holds in general.
— Trace spaces of full free product $C^*$-algebras
(2407.15985 - Ioana et al., 22 Jul 2024) in Remark 2.11, Section 2.5