密码 发表于 2025-3-23 12:20:01
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Potential Symmetries,n differential equations from point symmetries to contact symmetries, and, still more generally, to Lie-Bäklund symmetries, we could find more conservation laws, construct mappings to related differential equations, and determine more invariant solutions.BIPED 发表于 2025-3-24 01:28:11
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Lie Groups of Transformations and Infinitesimal Transformations,ties (1.88), the induced scaling transformations of all quantities (1.88), (1.89), and the induced scaling transformations preserving all constants (1.88), (1.91), are all examples of Lie groups of transformations. Scaling transformations are easily described in terms of their global properties as sdowagers-hump 发表于 2025-3-24 08:30:24
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Potential Symmetries, of the differential equation. In previous chapters we considered symmetries defined by infinitesimal transformations whose infinitesimals depend on independent variables, dependent variables, and derivatives of dependent variables. Such symmetries are . since at any point . the infinitesimals are dmonochromatic 发表于 2025-3-24 21:36:57
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George W. Bluman,Sukeyuki Kumeirst (1982) and second (1990) editions. The previous texts have been so comprehensive that it is dif?cult to imagine he could add more information to the existing chapters and create additional new chapters. One of the new chapters concerns the multiply-injured child, who presents an increasing probl