Fundamental Solution of the Anisotropic Porous Medium Equation

We establish the existence of fundamental solutions for the anisotropic porous mediumequation,u=∑~n(u) in ~n×(0,∞),where m,m,…,and mare positive constantssatisfying min{m } 1∑~n mi>n-2,and max1 i n{m} (1/n)(2+∑~n mi).