Endpoint estimates from restricted rearrangement inequalities

Let T be a sublinear operator such that (Tf)*(t) ≤ h(t,∥f∥ 1 ) for some positive function h(t, s) and every function / such that ∥f∥ ∞ ≤ 1. Then, we show that T can be extended continuously from a logarithmic type space into a weighted weak Lorentz space. This type of result is connected with the theory of restricted weak type extrapolation and extends a recent result of Arias-de-Reyna concerning the pointwise convergence of Fourier series to a much more general context.