engleski

Finite extensions of Bessel sequences

The paper studies finite extensions of Bessel sequences in infinitedimensional Hilbert spaces. We provide a characterization of Bessel sequences that can be extended to frames by adding finitely many vectors. We also characterize frames that can be converted to Parseval frames by finite-dimensional perturbations. Finally, some results on excesses of frames and near-Riesz bases are derived.

Bessel sequences ; frames ; Parseval frames

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