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Image of the standard positive cone under the braided standard isomorphism

Characterize the image of the standard positive cone of the von Neumann algebra A1 ⊠ A2 inside L^2(A1) ⊗ L^2(A2) under the canonical unitary I_⊠ that identifies L^2(A1 ⊠ A2) with L^2(A1) ⊗ L^2(A2) for actions of a quasi-triangular locally compact quantum group. Provide an explicit description analogous to the known characterization in the ordinary tensor product case.

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Background

The paper establishes a canonical unitary I_⊠ intertwining the standard representations and the unitary implementations for braided tensor products A1 ⊠ A2 arising from a quasi-triangular locally compact quantum group. While the unitary and modular conjugation are identified, the authors point out a gap: the structure of the standard positive cone under this identification is not determined.

In the ordinary tensor product case, the image of the positive cone in L2(A1 ⊗ A2) is known (see Miura–Tomiyama, 1984). Extending such a characterization to the braided tensor product would complete the standard form picture developed in the paper.

References

At the moment, it is not clear for us how to characterise the image of the standard positive cone in L2(A_1\boxtimes A_2) under I_\boxtimes (for a description of the positive cone in the case of ordinary tensor product, see ).

The standard construction for cocycle twisted and braided tensor product W$^*$-algebras (2508.00595 - Commer et al., 1 Aug 2025) in Introduction, after Theorem*, p. 2 (immediately following the stated main theorem)