A Quantum Analogue of the Pfaffian-Determinant Identity, An Algebraic and Geometric Study in the q-Skew-Symmetric Case

Abstract

This paper explores a quantum deformation of the classical identity Pf(A)^2 = det(A) for 2n by 2n skew-symmetric matrices A, which classically relates the square of the Pfaffian to the determinant. In the quantum setting, we study matrices whose entries lie in a noncommutative algebra and satisfy the q-skew-symmetry relations a_ji = -q times a_ij and a_ii = 0, where q is a nonzero complex parameter. This deformation introduces new algebraic structures and challenges in defining quantum analogues of classical invariants. We construct the quantum Pfaffian Pf_q(A) and quantum determinant det_q(A) using two main approaches: the Faddeev-Reshetikhin-Takhtajan (FRT) construction and quantum exterior algebras. We provide precise definitions, derive algebraic identities, and analyze properties of these quantum objects. Special attention is given to verifying the quantum analogue of the Pfaffian-determinant identity, q to the power c times Pf_q(A)^2 = det_q(A), in low-dimensional cases such as 2n = 4, using explicit symbolic computations. We also explore geometric interpretations within the context of braided vector spaces, quantum symplectic geometry, and deformations of volume forms. The paper includes examples and diagrams highlighting connections between combinatorics, representation theory, and noncommutative geometry. Potential applications are discussed in quantum invariant theory, low-dimensional topology, and categorified geometry. These results contribute to the broader understanding of quantum analogues of classical linear algebra and their role in quantum group theory.