@techreport{16CKMSW-NMFIrrational16, title = "Nonnegative Matrix Factorization Requires Irrationality", author = "Dmitry Chistikov and Stefan Kiefer and Ines Maru\v{s}i\'{c} and Mahsa Shirmohammadi and James Worrell", year = "2016", institution = "arxiv.org", note = "To appear in SIAM Journal on Applied Algebra and Geometry; available at \verb|http://arxiv.org/abs/1605.06848|", }