The Noisy Non-negative Matrix factorization (NMF) is: given a data matrix A (d × n), find non-negative matrices B,C (d × k, k × n respy.) so that A = BC + N , where N is a noise matrix. Existing polynomial time algorithms with proven error guarantees require each column N·,j to have l1 norm much smaller than ||(BC)·,j ||1, which could be very restrictive. In important applications of NMF such a...