The quantum toroidal superalgebra isomorphism for gl_{n|m}

Let $V=\mathbb{C}^{n+m}$ with the gradation defined by $\epsilon_i=(-1)^{\delta_{i>n}}$. The super $R$-matrix determines shuffle algebras $\mathcal{A}^+$ and $\mathcal{A}^-$, which combine with $U_t(\dot{\mathfrak{gl}}_{n|m})$ into the Drinfeld double

$$\mathcal{A}=\mathcal{A}^+\otimes U_t(\dot{\mathfrak{gl}}_{n|m})\otimes\mathcal{A}^-.$$

Quantum toroidal superalgebra isomorphism. There is an isomorphism

$$\mathcal{A}\cong U_{q,t}(\ddot{\mathfrak{gl}}_{n|m}),$$

where the quantum toroidal superalgebra on the right-hand side is defined as in the cited reference. The super-case construction is presented as conjectural and the paper stops short of implementing the missing parts, so the claimed isomorphism remains open.