This note is concerned with nonparanetric and semiparametric inference in regression models where regressors are not continuous. In economic practice, few explanatory variables are continuous. Many of the are dummics, qualitative variables, or counts; and otheThis note is concerned with nonparanetric and semiparametric inference in regression models where regressors are not continuous. In economic practice, few explanatory variables are continuous. Many of the are dummics, qualitative variables, or counts; and others though continuous in nature, are recorded at intervals and can be treated as discrete.[+][-]