2009/07/24 by S. Zubin Gautam, Gautam, S. Zubin
Mathematics · #Advanced Harmonic Analysis Research #Nonlinear Partial Differential Equations #Numerical methods in inverse problems
paper · pdf · doi:10.48550/arxiv.0907.4216
We provide sufficient normal curvature conditions on the boundary of a domain D ⊂ \BBR4 to guarantee unboundedness of the bilinear Fourier multiplier operator \TD with symbol χD outside the local L2 setting, i.e. from Lp1 (\BBR2) × Lp2 (\BBR2) → Lp3' (\BBR2) with ∑ (1)/(pj) = 1 and pj <2 for some j. In particular, these curvature conditions are satisfied by any domain D that is locally strictly convex at a single boundary point.