A conditional Lie-Bäcklund symmetry method and differential constraint method are developed to study the radially symmetric nonlinear convection-diffusion equations with source. The equations and the admitted conditional Lie-Bäcklund symmetries (differential constraints) are identified. As a consequence, symmetry reductions to two-dimensional dynamical systems of the resulting equations are derived due to the compatibility of the original equation and the additional differential constraint corresponding to the invariant surface equation of the admitted conditional Lie-Bäcklund symmetry.

中文翻译：

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有源的径向对称非线性对流扩散方程的条件 Lie-Bäcklund 对称性和微分约束

建立了条件Lie-Bäcklund对称法和微分约束法研究径向对称非线性对流扩散方程组。确定方程和承认的条件 Lie-Bäcklund 对称性（微分约束）。因此，由于原始方程的兼容性和对应于所承认的条件 Lie-Bäcklund 对称性的不变表面方程的附加微分约束，推导出所得方程的二维动力学系统的对称性减少。