Three representations of the fractional -Laplacian: semigroup, extension and Balakrishnan formulas
arXiv:2010.06933 · doi:10.1515/fca-2021-0042
Abstract
We introduce three representation formulas for the fractional -Laplace operator in the whole range of parameters and . Note that for this a nonlinear operator. The first representation is based on a splitting procedure that combines a renormalized nonlinearity with the linear heat semigroup. The second adapts the nonlinearity to the Caffarelli-Silvestre linear extension technique. The third one is the corresponding nonlinear version of the Balakrishnan formula. We also discuss the correct choice of the constant of the fractional -Laplace operator in order to have continuous dependence as and . A number of consequences and proposals are derived. Thus, we propose a natural spectral-type operator in domains, different from the standard restriction of the fractional -Laplace operator acting on the whole space. We also propose numerical schemes, a new definition of the fractional -Laplacian on manifolds, as well as alternative characterizations of the seminorms.
To appear in Fractional Calculus and Applied Analysis