Controlled $K$-frames in Hilbert $C^*$-modules
Controlled frames have been the subject of interest because of its ability to improve the numerical efficiency of iterative algorithms for inverting the frame operator. In this paper, we introduce the notion of controlled $K$-frame in Hilbert $C^{*}$-modules. We establish the equivalent condition for controlled $K$-frame. We investigate some operator theoretic characterizations of controlled $K$-frames and controlled Bessel sequences. Moreover we establish the relationship between the $K$-frames and controlled $K$-frames. We also investigate the invariance of a $C$-controlled $K$-frame under a suitable map $T$. At the end we prove a perturbation result for controlled $K$-frame.Controlled frames have been the subject of interest because of its ability to improve the numerical efficiency of iterative algorithms for inverting the frame operator. In this paper, we introduce the notion of controlled $K$-frame in Hilbert $C^{*}$-modules. We establish the equivalent condition for controlled $K$-frame. We investigate some operator theoretic characterizations of controlled $K$-frames and controlled Bessel sequences. Moreover we establish the relationship between the $K$-frames and controlled $K$-frames. We also investigate the invariance of a $C$-controlled $K$-frame under a suitable map $T$. At the end we prove a perturbation result for controlled $K$-frame.