The Gelfand widths of lp-ball for 0 < p <= 1
Résumé
We provide sharp lower and upper bounds for the Gelfand widths of ℓ p -balls in the N -dimensional ℓ q N -space for 0 < p ≤ 1 and p < q ≤ 2 . Such estimates are highly relevant to the novel theory of compressive sensing, and our proofs rely on methods from this area.