2010/10/28 by G. Serëgin, Seregin, Gregory, Luís Silvestre +5 · 4 citations
Computer Science · Mathematics · #Advanced Harmonic Analysis Research #Advanced Mathematical Modeling in Engineering #Analysis of PDEs (math.AP) #FOS: Mathematics #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.1010.6025
openalex publication_date 2010/10/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the validity and failure of Liouville theorems and Harnack inequalities for parabolic and elliptic operators with low regularity coefficients. We are particularly interested in operators of the form ∂t - Δ+b⋅∇ and -Δ+b⋅∇ with a divergence-free drift b. We prove the Liouville theorem and Harnack inequality when b∈ L_∞(BMO-1) resp. b∈ BMO-1 and provide a counterexample to such results demonstrating sharpness of our conditions on the drift. Our results generalize to divergence-form operators with an elliptic symmetric part and a BMO skew-symmetric part. We also prove the existence of a modulus of continuity for solutions to the elliptic problem in two dimensions, depending on the non-scale-invariant norm ‖b‖L1. In three dimensions, on the other hand, bounded solutions with L1 drifts may be discontinuous.