<正> Based on the concept of adiabatic invariant,the perturbation to Lie-Mei symmetry and adiabatic invariantsfor Birkhoffian systems are studied.The definition
<正> The new types of conserved quantities,which are directly induced by Lie symmetry of nonholonomicmechanical systems in phase space,are studied.Firstly,the c
<正> A complete approximate symmetry classification of a class of perturbed nonlinear wave equations isperformed using the method originated from Fushchich and