Hopf deformation conjecture for the zero-slope subalgebra and the positive BPS Lie algebra

Let $\mathcal{B}_{\mathbf{0}}^{+}$ be the slope subalgebra of the preprojective $K$-theoretic Hall algebra, and let $\mathfrak{n}_{Q}^{BPS}$ denote the positive half of the BPS Lie algebra associated with the quiver $Q$. Hopf deformation conjecture. The algebra $\mathcal{B}_{\mathbf{0}}^{+}$ is a Hopf algebra deformation of the universal enveloping algebra

$$U(\mathfrak{n}_{Q}^{BPS}).$$

This proposed relationship connects the slope-factorisation structure of the $K$-theoretic Hall algebra with the BPS Lie algebra arising in the cohomological setting. The source presents the statement only as a rough formulation, and no resolution is given.