Espaces BMO, inégalités de Paley et multiplicateurs idempotents
Generalizing the classical BMO spaces defined on the unit circle with vector or scalar values, we define the spaces and , where for x ≥ 0 and q ∈ [1,∞[, and where B is a Banach space. Note that and by the John-Nirenberg theorem. Firstly, we study a generalization of the classical Paley inequality and improve the Blasco-Pełczyński theorem in the vector case. Secondly, we compute the idempotent multipliers of . Pisier conjectured that the supports of idempotent multipliers of form a Boolean...