TY JOUR TI EXTREMISM AS A SOCIO-LEGAL DEFINITION IN LEGISLATIVE ACTS, LAW ENFORCEMENT PRACTICE AND THE UNDERSTANDING OF CITIZENS KW law enforcement officer KW concept KW extremism KW interpretation KW clarification JO VESTNIK ADVANCED TRAINING INSTITUTE OF THE MIA OF RUSSIA AU Evseev, I.V. AU Krivencov, R.O. AU Baulina, A.A. PY 2026 IS 0 PB All-Russian Advanced Training Institute of the Ministry of the Interior of the Russian Federation