1[1]Wu Zhuoqun,Zhao Junning,Yin Jingxue and Li Huilai,Nolinear Diffusion Equations,World Scientific Publishing Co.Pte.Ltd.,Singapore,2001.
2[2]Esteban,J.R.and Vazquez,J.L.,Homogeneous diffusion in R with power-like nonlinear diffusivity,Arch.Rat.Mech.Anal.,103(1)(1988),39-80.
3[3]Winkler,M.,Some results on degenerate parabolic equations not in divergence form,Ph.D.Thesis,RWTh Aachen,Germany,2000.
4[4]Dal Passo,R.and Luckhaus,S.,A degenerate diffusion problem not in divergence form,J.Differential Equations,69(1)(1987),1-14.
5[5]Bertsch,M.,Dal Passo,R.and Ughi,M.,Discontinuous viscosity solutions of a degenerate parabolic equation,Trans.Amer.Math.Soc.,320(2)(1990),779-798.
6[6]Bertsch,M.,Dal Passo,R.and Ughi,M.,Nonuniqueness of solutions of a degenerate parabolic equation,Ann.Mat.Pura Appl.,161(1992),57-81.
7[7]Bertsch,M.and Ughi,M.,Positivity property of viscosity solutions of a degenerate parabolic equation,Nonlinear Anal.,TMA,14(7)(1990),571-592.
8[8]Fukuda,I.,Ishii,H.and Tsutsumi,M.,Uniqueness of solutions to the Cauchy problem for ut - u△u +γ|∨u|2 = 0,Differential Integral Equations,6(6)(1993),1231-1252.
9[9]Zhan Yi,Theory of viscosity solutions and several classes of nonlinear degenerate equations,Ph.D.Thesis of Tsinghua University,Beijing,1993.
10[10]Lu Yunguang and Qian Liwen,Regularity of viscosity solutions of a degenerate parabolic equation,Proc.Amer.Math.Soc.,130(2002),999-1004.
8Shenghong Li Department of Mathematics,Zhejiang University,Hangzhou,310027,P.R.ChinaXiangao Liu Department of Mathematics,Fudan University,Shanghai,200433,P.R.China.The G Class of Functions and Its Applications[J].Acta Mathematica Sinica,English Series,2000,16(3):455-468.
