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The Dirichlet problem for elliptic equations in divergence and nondivergence form with singular drift term

Cristian Rios
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Abstract

Given two elliptic operators L and M in nondivergence form, with coefficients A_L(x), A_M(x) and drift terms b_L(x), b_M(x), respectively, satisfying a Carleson measure disagreement condition in a Lipschitz domain Omega in R^{n+1}, then their harmonic measures are mutually absolutely continuous. As an application of this, a new approximation argument and known results we obtain necessary and sufficient conditions for a single operator L (in divergence or nondivergence form) to have regular harmonic measure with respect to Lebesgue measure. The results are sharp in all cases.

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Cristian Rios. 2005-10-18. The Dirichlet problem for elliptic equations in divergence and nondivergence form with singular drift term. https://arxiv.org/abs/math/0510393

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