We establish nonparametric identification in a class of so-called index models using a novel approach that relies on general topological results. Our proof strategy imposes very weak smoothness conditions on the functions to be identified and does not require any large support conditions on the...

Models of simultaneous discrete choice may be incomplete, delivering multiple values of out- comes at certain values of the latent variables and covariates, and incoherent, delivering no val- ues. Alternative approaches to accommodating incompleteness and incoherence are considered in a unifying...