We use Salem's method [13, 14] to prove an inequality of Kwapień and Pełczyński concerning a lower bound for partial sums of series of bi-orthogonal vectors in a Hilbert space, or the dual vectors. This is applied to some lower bounds on L1 norms for orthogonal expansions.
|Number of pages||8|
|Journal||Journal of Inequalities in Pure and Applied Mathematics|
|Publication status||Published - 2009|