In this article, we propose a new class of semiparametric instrumental variable models with partially varying coefficients, in which the structural function has a partially linear form and the impact of endogenous structural variables can vary over different levels of some exogenous variables....

We study Aumann and Serrano's (2008) risk index for sums of gambles that are not dependent. If the dependent parts are similarly ordered, then the risk index of the sum is always larger than the minimum of the risk indices of the two gambles. For negative dependence, the risk index of the sum is...