| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4620785 | Journal of Mathematical Analysis and Applications | 2008 | 6 Pages |
Abstract
We obtain a condition implying that the union of two frame sequences is also a frame sequence. Christensen found a condition for this in terms of orthogonal projections. We phrase our condition by use of the angle between closed subspaces. Also a lower bound formula is obtained. We then apply the results to find conditions for a frame containing a Riesz basis to be a Riesz frame.
Related Topics
Physical Sciences and Engineering
Mathematics
Analysis
