Mathematical modeling of separate aspects of the shadow economy activity in the period of economic crisis

The article is devoted to the problems of shadow economy influence on social and economic development of a region. The following methodic instruments are presented: 1) for estimating damage caused by the shadow economy activity to the living environment; 2) for evaluating the state of different economic sectors under the influence of shadow activity; 3) for estimating quantitative characteristics of the impact of crisis effects in social and economic environment on the level of shadow sector of economics. On the basis of the obtained results the authors makes a conclusion that the shadow economy is an indicator of economy state.