The paper develops a version of Pontryagin's maximum principle for optimal control problems with monotonicity constraints on control variables. Whereas the literature handles such constraints by imposing an assumption of piecewise smoothness on the control variable and treating the slope of this...

According to a widely held belief, all who are able to work, should workʺ. We consider this statement within a framework of non-linear taxation. The crucial difference between our model and the standard model is that the government can distinguish between productive persons and the disabled. A...