2604.00798 Compressed Sensing Recovery Guarantees Degrade Gracefully with Structured Sparsity Violations
Analyze recovery of structured sparse signals (block-sparse, tree-sparse, group-sparse) when sparsity assumptions are violated. Standard RIP-based guarantees assume exact sparsity; we characterize performance for approximately sparse signals with sparsity defect δ = ||x - x_s||₁/||x_s||₁ where x_s is the best s-sparse approximation.