The work is devoted to the problem of defining the category of «money». To correctly define the concept of «money», one should: 1) conduct a logical analysis of the main forms and types of money for what unites them all, while 2) take into account that money does not exist outside time and space, but in the economic system. A sign is an object that replaces another object in someone's mind (which is the meaning of a sign). Еconomic relations in many cases are fixed in symbolic form. What is included in the symbolic subsystem of the economy? – ​signs of property rights; debt signs; and finally, money. Is money a sigh? Money is a legitimate sign of value. Money, in accordance with our definition (and with the real state of affairs), is an object that denotes a particular measure of value. At the same time, what kind of object is the bearer of the sign is a question that has nothing to do with the essence of money. Money can be classified according to what is the substrate of the sign: metal, paper (banknotes), credit (records on bank accounts), electronic. The differences in the substrates of money are the basis for the advancement of various genetic theories of the origin of money. all of them, in essence, can be reduced to the commodity-metal concept and the concept of state-legal (nominalist, contractual, debt). The presence of these two genetic concepts is associated with two fundamentally different types of legitimization of banknotes: 1) direct, when the substrate of the sign has a value that it symbolizes (coins made of gold or silver); 2) mediated (fiat money). The solution to this problem of the external duality of money is in the understanding that money is essentially a sign. This is what unites everyone. The difference between the forms of money is in the form of legitimization (directly commodity, or legal).

The purpose of the article is to study the economic nature of money. The author notes that in a number of the most common monetary theories, the question of the nature of money is not even raised. The author shows that a number of modern theories of money are related to the nominalist theory, as well as to the concept of the credit nature of money. However, the nature of money in these concepts either does not receive a clear definition, or is based on an erroneous interpretation of facts. The author begins the answer to the question about the nature of money by analyzing the relations of commodity production underlying the origin of money. The author is based on the priority of the reproductive approach and believes that subjective psychological assessments of the usefulness of goods are not the basis of the proportions of exchange. Money is considered as a separate objective being of the objective property of value inherent in goods. Since capital in the modern economy is mainly in the form of fictitious capital, it is its turnover that acts as the basis for a credit issue that ensures monetary circulation. The regulated nature of credit relations marks the undermining of the properties of money as a product of the spontaneous movement of commodity production.

The purpose of the article is to develop a model describing the spread of the multiplicative process in the sphere of investment from the standpoint of its fractality. The relevance of the purpose is determined by the need for investment in the Russian economy to ensure its growth. Modeling the multiplicative process will allow to take into account its consequences as part of the results of large investment projects, as well as to actively manage multiplicative processes, enhancing or decreasing the rates of economic growth with their help. The objective of the article is to form a model that describes the internal components of the multiplicative process interaction with the investment accelerator. The article forms the hypothesis that the main stages of this process are self-similar, therefore, the process is fractal. This model has the following scientific novelty. (1) With the help of schemes of income's multiplicative transfer chains, the fractality of both these chains themselves and the process of their amplification by the investment multiplier is substantiated. (2) The proposed model is based on the description of the internal components of the multiplicative process's spread in the sphere of investment, which distinguishes it from regression or matrix models for determining the value of the investment multiplier. (3) As a result of modeling the stages of the multiplicative process in the sphere of investment, a formula for the investment multiplier was derived, taking into account the action of the investment accelerator. (4) The carried out practical calculations made it possible to determine the difference in the values of the investment multiplier for different regions of Russia. This, in turn, made it possible to theoretically substantiate the use of the difference in the values of regional multipliers, based on the difference in the structures of regional economies, as a basis for a tool for managing the Russian economy by identifying existing potential growth points and creating new ones. The proposed modeling, by taking into account the consequences of the multiplicative process spread when calculating the effectiveness of large investment projects, will increase the implementation of these projects predictability and reduce the risk of negative consequences.

The machine is used in a continuous production process in the enterprise that is a market participant. During its use, it can be subject to random failure after which losses occur due to interruption of the process. After failure, the machine is decommissioned and disposed of. Over time, the failure rate increases. Under these conditions, it turns out to be beneficial for the enterprise to set an assigned service life for the machine, after which (if no failure has occurred) it must be disposed of. We solve the problem of optimizing the assigned service life. Usually, to solve this problem, various optimality criteria are used, for example, average costs per unit of time (including the time to eliminate the consequences of a failure), reliability indicators, or other indicators that do not fully reflect the commercial interests of the enterprise owning the machine. Using the principles and methods of asset valuation, we build a mathematical model that allows us to calculate the optimal assigned life of the machine and at the same time assess the market value of the work performed by it. At the same time, in this problem, the optimality criterion is the ratio of the expected discounted costs to the expected discounted volume of work performed by the machine (in units of operating time). Using this criterion, the market value of the enterprise owning the machine will be the highest. The proposed model allows us to estimate the market value of the serviceable machine knowing its age. We compare the proposed and alternative optimality criteria. We give an example in which machine failures have a Rayleigh distribution. The proposed general approach can be used both in solving other optimization problems of reliability theory and for practical valuation of some types of machinery and equipment.

A 2018 article by the authors described a dynamic behavior model of the agents’ population belonging to different income groups in the transition from a pay-as-you-go to a mixed pension system. The model is based on the assumption that wealthier participants are characterized by a lower rate of income discounting, which effectively means an orientation toward a longer planning horizon. In this paper we propose and explore an advanced model. It significantly improves the approximation of trajectories observed in Argentina after the pension reform of 1993, which is largely similar to the failed Russian reform of 2002. The model shows that as income increases, the share of the corresponding income group who prefers keeping in the shadows should fall. This pattern is consistent with observations. The model helps to explain why pension reforms in many countries have resulted in an expansion of the shadow sector. The impact of the minimum pension, the rate of return on pension savings and the retirement age on the levels of participation of different income groups in the pension system is studied. Based on the results, we formulate recommendations for continuing the pension reform in Russia.

High mortality in road accidents is an urgent problem for Russia, which at the same time is underestimated. The calculation of the dynamics of the potentially unborn people due to the death of women in reproductive age in the road accidents showed that even in conditions of low birth rates, Russia annually loses thousands of people in the form of unrealized fertility potential. Moreover, the demographic damage that actually occurred in the past leads to the economic losses in future. The proposed model of demographic potentials allows us to calculate undervalued losses, both in demography and in the economy. It became obvious that economic losses due to the inertia of demographic processes are of a delayed nature. This means that it is impossible to avoid these losses, but they can be managed. The article offers one of the tools for such management. Since the demographic potential model allows us to obtain data on economic damage in the past, all the market participants can receive data in advance about the damage that has developed for the number of workers in a branch in the medium term. And thanks to the data on employment industry structure, we will be able to answer in advance where exactly the personnel shortage would develop. In the conditions of planned industrial foresights, as well as limited access to effective foreign technologies, it is really difficult to overestimate the importance of such knowledge.

Industrial waste involvement in road construction projects is one of the most prospective areas for waste management industry development in Russia. The introduction and scaling up of this practice will simultaneously reduce the costs of both road construction and waste storage. In the article, the authors attempted to evaluate the economic potential of using industrial by-products (using the example of ash and slag waste) in the road construction industry as an embankment of a roadbed. As the result, it was revealed that the economic potential for utilizing ash and slag waste as a road embankment can be up to 7,9 million tons annually. At the same time, it will be economically feasible to involve ash and slag waste in road construction only if the ash dump is located at a distance of no more than 130–150 kilometer from the construction site. The study also discovers that depending on the ash dump and open pits with traditional resources location, the effect in reducing the building highways costs across the country can range from 104,70 million to 30 359,48 million rubles. The authors concluded that to reduce the anthropogenic impact of the road construction industry, the government should form a mechanism stimulating the use of industrial waste keeping technological capabilities and economic feasibility of the process. Based on foreign experience, the authors proposed to use the effective disposal radius mechanism, which preserves the principle of economic feasibility of using ash and slag waste in the road construction projects.

The evolution of socio-economic relations, studied in the dynamics of the development of such a phenomenon as structural changes in industry caused by the diffusion of knowledge-intensive technologies of a convergent type, is most consistently revealed within the framework of the mesoeconomic production system of the country level, through appropriate modeling of characteristic objects and processes. The mesoeconomic modeling of the industrial sector of the American economy, which entered a qualitatively new period of reindustrial development a decade ago, seems relevant. The aim of this study is to use elements and modeling systems that meet the requirements of sectoral and regional mesoeconomics to assess the structural shifts that took place in the US industry in the period 2011–2020 under the influence of convergent technologies. To solve this problem, the DEA-method is used, developed and tested by the American scientists and is aimed at calculating the convergent resonance index and the indicator of the comparative efficiency of the objects under study. Based on the results of constructing models of the technological efficiency of the US industry in space-time, oriented to the input and output parameters, an assessment of the structural shifts of the American industry, both sectoral and spatial-regional components of the US mesoeconomic system, is presented. The conclusion is made about the generally successful structural modernization of American industry in the inter-crisis period, characterized as the initial stage of the reindustrial development of the United States on the basis of convergent technologies of the sixth technological order. The problems of the initial stage of American reindustrialization associated with a small increase in industrial production within the framework of the national knowledge economy and the strengthening of structural imbalances in its spatial development are identified. At the same time, a high level of efficiency of modernization of the main industries of the United States in the considered period of time was noted, associated with the active diffusion of convergent technologies.