gilan province is among the most important regions of iran for rice production. the general aim of this research is to determine the best variety of rice for planting, so that the minimum level for farmer's expected living gross margin can be provided. on the other hand, determining the best variety with regard to the risk in price is another aim of this research. to this end two risk models ba...

We study an extension of first-order logic that allows to express cardinality conditions in a similar way as SQL’s COUNT operator. The corresponding logic FOC(P) was introduced by Kuske and Schweikardt [16], who showed that query evaluation for this logic is fixedparameter tractable on classes of databases of bounded degree. In the present paper, we first show that the fixed-parameter tractabil...

This paper addresses the crucial issue in the design of a proof development system of how to deal with partial functions and the related question of how to treat undefined terms. Often the problem is avoided by artificially making all functions total. However, that does not correspond to the practice of everyday mathematics. In type theory partial functions are modeled by giving functions extra...

This paper describes a strategy for structural estimation of economic models that I will refer to as SML based on FOCs. In this approach, one uses simulated maximum likelihood (SML) to estimate the structural parameters that appear in the Euler or first order conditions (FOCs) solved by an optimizing economic agent. I will argue that the SML based on FOCs approach has certain advantages over th...

We derived the Kuhn-Tucker theorem by assuming regularity of the binding constraints. With the possibility of corner solutions, regularity is too stringent. The regularity condition will not necessarily apply throughout the constraint set. Verifying the regularity condition requires knowing the optimal solution, but the first-order conditions will not identify the optimal solution unless the re...

In this paper, we answer the question under which conditions the porousmedium equation with convection and with periodic boundary conditions possesses gradient-type Lyapunov functionals (first-order entropies). It is shown that the weighted sum of first-order and zeroth-order entropies are Lyapunov functionals if the weight for the zeroth-order entropy is sufficiently large, depending on the st...