Title of article :
Ultra Bessel sequences in direct sums of Hilbert spaces
Author/Authors :
Abdollahpour, M.R Department of Mathematics - Faculty of Mathematical Sciences - University of Mohaghegh Ardabili - Ardabil, Islamic Republic of Iran , Rahimib, A Department of Mathematics - Faculty of Mathematical Sciences - University of Mohaghegh Ardabili - Ardabil, Islamic Republic of Iran
Abstract :
In this paper, we establish some new results in ultra Bessel se-
quences and ultra Bessel sequences of subspaces. Also, we in-
vestigate ultra Bessel sequences in direct sums of Hilbert spaces. Specially, we show that f( fi; gi)g1 i=1 is a an ultra Bessel sequence for Hilbert space H K if and only if f fig1
i=1 and fgig1 i=1 are ultra Bessel sequences for Hilbert spaces H and K; respectively.
Keywords :
Frame of subspaces , Ultra Bessel sequence , Ultra Bessel sequences in direct sums of Hilbert spaces
Journal title :
Astroparticle Physics
