Support Recovery for Orthogonal Matching Pursuit: Upper and Lower bounds

We study the problem of sparse regression where the goal is to learn a sparse vector that best optimizes a given objective function. Under the assumption that the objective function satisfies restricted strong convexity (RSC), we analyze orthogonal matching pursuit (OMP), a greedy algorithm that is used heavily in applications, and obtain a support recovery result as well as a tight generalization error bound for the OMP estimator. Further, we show a lower bound for OMP, demonstrating that both our results on support recovery and generalization error are tight up to logarithmic factors. To the best of our knowledge, these are the first such tight upper and lower bounds for any sparse regression algorithm under the RSC assumption.