TY JOUR TI Analysis and mathematical modeling of sectoral differentiation of nominal wages in the Russian Federation KW wages KW nominal wages KW sectoral differentiation KW labor market KW economic and mathematical modeling KW time series analysis KW trend models KW index analysis KW variational analysis JO Journal of Applied Research AU Vasilyeva, T.V. AU Sinko, A.K. AU Zaretskaya, Z.I. PY 2026 IS 0 PB ITBO University