Ultra Bessel sequences in direct sums of Hilbert spaces

Document Type: Research Paper

Authors

1 University of Mohaghegh Ardabili

2 University of Maragheh

Abstract

In this paper, we establish some new results in ultra Bessel sequences and ultra Bessel sequences of subspaces. Also, we investigate ultra Bessel sequences in direct sums of Hilbert spaces. Specially, we show that {( fi, gi)}i=1 is a an ultra Bessel sequence for Hilbert space H ⊕ K if and only if { fi}i=1 and {gi}i=1 are ultra Bessel sequences for Hilbert spaces H and K, respectively.

Keywords


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