2010/02/03 by Steve Hofmann, Svitlana Mayboroda, Hofmann, Steve +3 · 3 citations
Mathematics · #Advanced Harmonic Analysis Research #Advanced Mathematical Physics Problems #FOS: Mathematics #Functional Analysis (math.FA) #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.1002.0792
openalex publication_date 2010/02/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let L be a second order divergence form elliptic operator with complex\nbounded measurable coefficients. The operators arising in connection with L,\nsuch as the heat semigroup and Riesz transform, are not, in general, of\nCalder 'on-Zygmund type and exhibit behavior different from their counterparts\nbuilt upon the Laplacian. The current paper aims at a thorough description of\nthe properties of such operators in Lp, Sobolev, and some new Hardy spaces\nnaturally associated to L.\n First, we show that the known ranges of boundedness in Lp for the heat\nsemigroup and Riesz transform of L, are sharp. In particular, the heat\nsemigroup e-tL need not be bounded in Lp if p not\∈\n[2n/(n+2),2n/(n-2)]. Then we provide a complete description of it all\nSobolev spaces in which L admits a bounded functional calculus, in\nparticular, where e-tL is bounded.\n Secondly, we develop a comprehensive theory of Hardy and Lipschitz spaces\nassociated to L, that serves the range of p beyond [2n/(n+2),2n/(n-2)].\nIt includes, in particular, characterizations by the sharp maximal function and\nthe Riesz transform (for certain ranges of p), as well as the molecular\ndecomposition and duality and interpolation theorems.\n