Carro Rossell, María Jesús2019-04-262019-04-2620020214-1493https://hdl.handle.net/2445/132424Given a sublinear operator T satisfying that !Tf!Lp(ν) ≤ C p−1 !f!Lp(µ), for every 1 < p ≤ p0, with C independent of f and p, it was proved in [C] that sup r>0 ! ∞ 1/r λν T f (y) dy 1 + log+ r ! ' M |f(x)|(1 + log+ |f(x)|) dµ(x). This estimate implies that T : L log L → B, where B is a rearrangement invariant space. The purpose of this note is to give several characterizations of the space B and study its associate space. This last information allows us to formulate an extrapolation result of Zygmund type for linear operators satisfying !Tf!Lp(ν) ≤ Cp!f!Lp(µ), for every p ≥ p0.11 p.application/pdfeng(c) Universitat Autònoma de Barcelona, 2002Anàlisi harmònicaTeoria d'operadorsHarmonic analysisOperator theoryinfo:eu-repo/semantics/article5104442019-04-26info:eu-repo/semantics/openAccess