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Fully explicit FRT-based proof in arbitrary dimension

Develop a fully explicit, inductive, and algebraically detailed proof within the Faddeev–Reshetikhin–Takhtajan (FRT) framework of the identity q^{binom(n,2)} · Pf_q(A)^2 = det_q(A) for all even sizes 2n, where A is a 2n × 2n matrix with entries in a noncommutative algebra satisfying the q-skew-symmetry relations a_{ji} = −q a_{ij} and a_{ii} = 0, Pf_q(A) is the quantum Pfaffian defined via the quantum exterior algebra, and det_q(A) is the quantum determinant arising from the FRT construction.

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Background

The paper constructs the quantum Pfaffian Pf_q(A) and quantum determinant det_q(A) in the setting of q-skew-symmetric matrices using the FRT construction and quantum exterior algebras. It verifies the quantum Pfaffian–determinant identity in low-dimensional cases and outlines how the exponent depends on dimension.

While the authors present evidence and outlines for the general identity, they note that a complete, fully detailed algebraic proof valid for all even dimensions 2n, carried out entirely within the FRT framework and carefully handling braided antisymmetry and noncommutativity, is still lacking. Establishing such a proof would confirm the identity at full generality and clarify the precise bookkeeping of q-powers arising from braid crossings.

References

Although we have established the identity q{\binom{n}{2}\,Pf_q(A)2 = \det_q(A) rigorously for low-dimensional cases and provided an outline for the general case, a fully explicit, inductive, and algebraically detailed proof within the Faddeev–Reshetikhin–Takhtajan (FRT) framework remains to be formulated.

A Quantum Analogue of the Pfaffian-Determinant Identity, An Algebraic and Geometric Study in the q-Skew-Symmetric Case (2508.11634 - Safadi, 24 Jul 2025) in Section 7.2 (Open Problems and Conjectures)