%0 Journal Article
%T Ultra Bessel sequences in direct sums of Hilbert spaces
%J Wavelet and Linear Algebra
%I Vali-e-Asr university of Rafsanjan
%Z 2383-1936
%A Abdollahpour, M. R.
%A Rahimi, A.
%D 2015
%\ 09/01/2015
%V 2
%N 1
%P 55-64
%! Ultra Bessel sequences in direct sums of Hilbert spaces
%K Frame of subspaces
%K Ultra Bessel sequence
%R
%X 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.
%U https://wala.vru.ac.ir/article_14270_489abf58eb663e969ea22c4d90360acb.pdf