Посилання:On the n-Dimensional Porous Medium Diffusion Equation and Global Actions of the Symmetry Group / J.A. Franco // Symmetry, Integrability and Geometry: Methods and Applications. — 2013. — Т. 9. — Бібліогр.: 17 назв. — англ.
By restricting to a special class of smooth functions, the local action of the symmetry group is globalized. This special class of functions is constructed using parabolic induction.