Resumen de On the range space of Yano's extrapolation theorem and new extrapolation estimates at infinity
Given a sublinear operator T satisfying that ||Tf||Lp(?) = C/(p-1) ||f||Lp(µ), for every 1 < p = p0, with C independent of f and p, it was proved in [C] that... [check the paper abstract for the formula] 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(?) = Cp|| f ||Lp(µ), for every p = p0.
[Proceedings of the 6th International Conference on Harmonic Analysis and Partial Differential Equations, El Escorial (Madrid), 2002].
