Equations with nonnegative characteristic form. II (original) (raw)
2009, Journal of Mathematical Sciences
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The paper advances the theory of differential operators with nonnegative characteristic form, focusing on the local smoothness and hypoellipticity of second-order equations. Building on previous work, it discusses necessary and sufficient conditions for hypoellipticity, particularly for equations with variable coefficients, and introduces methods for assessing the asymptotic properties of solutions in unbounded domains.
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