On the Reachability of a Feedback Controlled Leontief-Type Singular Model Involving Scheduled Production, Recycling and Non-Renewable Resources

This paper proposes and studies the reachability of a singular regular dynamic discrete Leontief-type economic model which includes production industries, recycling industries, and non-renewable products in an integrated way. The designed prefixed final state to be reached, under discussed reachability conditions, is subject to necessary additional positivity-type constraints which depend on the initial conditions and the final time for the solution to match such a final prescribed state. It is assumed that the model may be driven by both the demand and an additional correcting control in order to achieve the final targeted state in finite time. Formal sufficiency-type conditions are established for the proposed singular Leontief model to be reachable under positive feedback, correcting controls designed for appropriate demand/supply regulation. Basically, the proposed regulation scheme allows fixing a prescribed final state of economic goods stock in finite time if the model is reachable.

Modification of the Ghosh model structure in inter-sectoral analysis

The current Ghosh model is based on the use of value-added forecast data. The forecasts of gross domestic product and value added have long and regularly been developed by different national and international economic and financial structures, including governmental ones. The level of methods and accuracy of such forecasts is quite high as compared with the final demand forecasts on which the Leontief model is based. Therefore, from the econometric point of view, the accuracy of predictions of output made by using the Ghosh model should be at least not worse than that provided by the classical Leontief model. The modified Ghosh model formally differs from its current model by the presence of a new matrix. However, this difference is only a structural feature, and in mathematical terms these models are identical. At the same time, the modified Ghosh model is more attractive and promising than the current one due to the following factors. It uses one matrix instead of two matrices that appear in the current model. The modified model has a structure (unlike the current one) similar to the structure of the classical Leontief model. Due to this, the modified model is more understandable and easy to use. However, the most important feature lies in the fact that the use of a new matrix significantly expands the possibilities of theoretical research within the input-output structures. Due to constructing a new matrix in the modified Ghosh model, new relations between the vectors of final demand and value added were discovered, which can be efficiently used in balancing the system of input-output matrices. It was also established that the corresponding matrices of the classical Leontief model and the modified Ghosh model have identical diagonal elements in pairs, and this is useful in various analytical studies. Keywords: modified Ghosh model, input-output, Leontief model, value added, final demand

Solving Systems of Linear Equations under Conditions of Uncertainty on the Example of the Leontief Model

The paper presents various methods of solving systems of linear equations under conditions of uncertainty. In a situation when the parameters of such systems cannot be precisely determined with real numbers, they can be represented by interval numbers, fuzzy numbers or ordered fuzzy numbers. Solutions of systems of linear equations with such representations of parameters are shown in the example of Leontief input-output model. It has also been shown that when ordered fuzzy numbers are applied, their additional feature – orientation – can broaden and deepen economic analysis.