Universality classes for centrally weighted small-step models

Let ${\mathcal{S}}$ be one of the 19 small-step lattice-path models with finite non-zero orbit sum, and consider its centrally weighted walk model. Let $Q(1,1;t)$ be the corresponding generating function, and let the universality classes be the classes determined by the minimum of the inventory on the quarter-plane cone. Garbit, Mustapha and Raschel's universality-class conjecture. The divisions into universality classes for centrally weighted walk models are given by the Garbit–Mustapha–Raschel conjecture. The source states that this is verified for GB walks with central weighting, but does not establish it for all 19 models.