The reconstruction formula for Banach frames and duality

DANIEL CARANDO; SILVIA LASSALLE; PABLO SCHMIDBERG

JOURNAL OF APPROXIMATION THEORY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2011 vol. 163 p. 640 - 651

0021-9045

We study conditions on a Banach frame that ensures the validity of a reconstruction formula. In particular, we show that any Banach frames for (a subspace of) $L_p$ or $L_{p,q}$ ($1 le p < infty$) with respect to a solid sequence space always satisfies an unconditional reconstruction formula. The existence of reconstruction formulae allows us to prove some James-type results for atomic decompositions: an unconditional atomic decomposition (or unconditional Schauder frame) for $X$ is shrinking (respectively, boundedly complete) if and only if $X$ does not contain an isomorphic copy of $ell_1$ (respectively, $c_0$).