A Trivial Observation related to Sparse Recovery

We make a trivial modification to the elegant analysis of Garg and Khandekar (\emph{Gradient Descent with Sparsification} ICML 2009) that replaces the standard Restricted Isometry Property (RIP), with another RIP-type property (which could be simpler than the RIP, but we are not sure; it could be as hard as the RIP to check, thereby rendering this little writeup totally worthless).