2,986 research outputs found
A logarithmic Hardy inequality
We prove a new inequality which improves on the classical Hardy inequality in
the sense that a nonlinear integral quantity with super-quadratic growth, which
is computed with respect to an inverse square weight, is controlled by the
energy. This inequality differs from standard logarithmic Sobolev inequalities
in the sense that the measure is neither Lebesgue's measure nor a probability
measure. All terms are scale invariant. After an Emden-Fowler transformation,
the inequality can be rewritten as an optimal inequality of logarithmic Sobolev
type on the cylinder. Explicit expressions of the sharp constant, as well as
minimizers, are established in the radial case. However, when no symmetry is
imposed, the sharp constants are not achieved among radial functions, in some
range of the parameters
The fractional Hardy inequality with a remainder term
We calculate the regional fractional Laplacian on some power function on an
interval. As an application, we prove Hardy inequality with an extra term for
the fractional Laplacian on the interval with the optimal constant. As a
result, we obtain the fractional Hardy inequality with best constant and an
extra lower-order term for general domains, following the method developed by
M. Loss and C. Sloane [arXiv:0907.3054v1 [math.AP]]Comment: Major change
Self-improvement of pointwise Hardy inequality
We prove the self-improvement of a pointwise -Hardy inequality. The proof
relies on maximal function techniques and a characterization of the inequality
by curves
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