To prevent identifiability issues of the covariate parameters, we reparametrize the model and choose one cell type k as a reference, forcing its covariates \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\beta }_{k}=0$$\end{document}βk=0 as in Maier et al.11 (Methods—“Automatic reference selection”).
