Central elements of the degenerate quantum general linear group
Hengyun Yang, Yang Zhang
TL;DR
The paper constructs central elements for the degenerate quantum general linear group $U_q(rak{gl}_{m,n})$, including an explicit quantum Casimir, by leveraging explicit $L$-operators and a partial-trace centrality framework. It introduces a spectral-parameter universal $L$-operator $L(x)$ that satisfies the quantum Yang–Baxter equation with the fundamental $R$-matrix, enabling an $RLL$ realisation of the algebra. The authors also develop an explicit $RLL$ realisation via Hopf-algebra isomorphisms between the standard degenerate quantum group and a universal RTT algebra, providing concrete mappings and a detailed ${ m U}_q(rak{gl}_{1,1})$ example. These results connect degenerate quantum groups to integrable systems and offer tools for studying their representation theory and potential lattice models.
Abstract
We construct central elements of the degenerate quantum general linear group introduced by Cheng, Wang and Zhang. In particular, we give an explicit formula for the quantum Casimir element. Our method is based on the explicit $L$ operators. Moreover, we construct a universal $L$ operator, which is a spectral parameter-dependent solution of the quantum Yang-Baxter equation in the tensor product of the degenerate quantum general linear group and the endomorphism ring of its natural representation. This construction leads to the FRT approach to the degenerate quantum general linear group.
