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Convergence of the Dirichlet solutions of the very fast diffusion equation

Analysis of PDEs 2010-12-16 v1

Abstract

For any 1<m<0-1<m<0, μ>0\mu>0, 0u0L(R)0\le u_0\in L^{\infty}(R) such that u0(x)(μ0mx)1mu_0(x)\le (\mu_0 |m||x|)^{\frac{1}{m}} for any xR0|x|\ge R_0 and some constants R0>1R_0>1 and 0<μ0μ0<\mu_0\leq \mu, and f,gC([0,))f,\,g \in C([0,\infty)) such that f(t),g(t)μ0f(t),\, g(t) \geq \mu_0 on [0,)[0,\infty) we prove that as RR\to\infty the solution uRu^R of the Dirichlet problem ut=(um/m)xxu_t=(u^m/m)_{xx} in (R,R)×(0,)(-R,R)\times (0,\infty), u(R,t)=(f(t)mR)1/mu(R,t)=(f(t)|m|R)^{1/m}, u(R,t)=(g(t)mR)1/mu(-R,t)=(g(t)|m|R)^{1/m} for all t>0t>0, u(x,0)=u0(x)u(x,0)=u_0(x) in (R,R)(-R,R), converges uniformly on every compact subsets of R×(0,T)R\times (0,T) to the solution of the equation ut=(um/m)xxu_t=(u^m/m)_{xx} in R×(0,)R\times (0,\infty), u(x,0)=u0(x)u(x,0)=u_0(x) in RR, which satisfies Ru(x,t)dx=Ru0dx0t(f(s)+g(s))ds\int_Ru(x,t)\,dx=\int_Ru_0dx-\int_0^t(f(s)+g(s))\,ds for all 0<t<T0<t<T where 0T(f+g)ds=Ru0dx\int_0^T(f+g)\,ds=\int_Ru_0dx. We also prove that the solution constructed is equal to the solution constructed in [Hu3] using approximation by solutions of the corresponding Neumann problem in bounded cylindrical domains.

Keywords

Cite

@article{arxiv.1012.3218,
  title  = {Convergence of the Dirichlet solutions of the very fast diffusion equation},
  author = {Kin Ming Hui and Sunghoon Kim},
  journal= {arXiv preprint arXiv:1012.3218},
  year   = {2010}
}

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33 pages