Lacunary convergence of series in L0 revisited.
A simpler proof is given for the recent result of I. Labuda and the author that a series in the space L0 (lambda) is subseries convergent if each of its lacunary subseries converges.
A simpler proof is given for the recent result of I. Labuda and the author that a series in the space L0 (lambda) is subseries convergent if each of its lacunary subseries converges.
A theorem of Lusin states that every Borel function onRis equal almost everywhere to the derivative of a continuous function. This result was later generalized to Rn in works of Alberti and Moonens-Pfeffer. In this note, we prove direct analogs of these results on a large class of metric measure spaces, those with doubling measures and Poincaré inequalities, which admit a form of differentiation by a famous theorem of Cheeger.