TY - JOUR ID - Tsyfra2021 LB - Tsyfra2021 AU - Tsyfra, Ivan TI - On classical symmetries of ordinary differential equations related to stationary integrable partial differential equations ST - On classical symmetries of ordinary differential equations related to stationary integrable partial differential equations JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2021 VL - 41 IS - 5 SP - 685 EP - 699 DO - https://doi.org/10.7494/OpMath.2021.41.5.685 UR - https://doi.org/10.7494/OpMath.2021.41.5.685 AB - We study the relationship between the solutions of stationary integrable partial and ordinary differential equations and coefficients of the second-order ordinary differential equations invariant with respect to one-parameter Lie group. The classical symmetry method is applied. We prove that if the coefficients of ordinary differential equation satisfy the stationary integrable partial differential equation with two independent variables then the ordinary differential equation is integrable by quadratures. If special solutions of integrable partial differential equations are chosen then the coefficients satisfy the stationary KdV equations. It was shown that the Ermakov equation belong to a class of these equations. In the framework of the approach we obtained the similar results for generalized Riccati equations. By using operator of invariant differentiation we describe a class of higher order ordinary differential equations for which the group-theoretical method enables us to reduce the order of ordinary differential equation. KW - ordinary differential equation KW - partial differential equation KW - integrability KW - symmetry KW - quadrature KW - Lie transformation group SN - 1232-9274 ER -