  Approximate duality of frame pairs have been investigated by Christensen and
Laugesen in (Sampl. Theory Signal Image Process., 9, 2011, 77-90), with the
motivation to obtain an important applications in Gabor systems, wavelets and
general frame theory. In this paper we obtain some of the known results in
approximate duality of frames to K-g-frames. We also obtain new K-g-frames and
approximate K-g-duals from a K-g-frame and an approximate K-g-dual. Finally, we
give an equivalent condition under which the subsequence of a K-g-frame still
to be a K-g-frame.
