wetlands as a situ for the growth of native plants, as a habitat for certain species of fish and aquatic birds, and because of their potential economic, cultural and recreational services, are valuable heritage so their protection and conservation is very essential. mostly due to the absence of wetlands services’ valuation, lack of special regulations, and lack of guarantee for these properties...

We propose a framework for nonparametric identification and estimation of discrete choice models with unobserved sets. recover the joint distribution sets preferences from panel dataset on choices. assume that either latent are sparse or is sufficiently long. Sparsity requires number possible to be relatively small. It satisfied, instance, when nested, they form partition. Our procedure comp...