1. This paper investigates the conditions under which a nonnegative matrix factorization is partially identifiable.
2. It provides a mathematically rigorous theorem of a restricted version of the data-based uniqueness theorem, relying on simple sparsity and algebraic conditions.
3. It also presents a geometric interpretation of the restricted DBU theorem, leading to another partial identifiability result in the case r=3, as well as sequential partial identifiability results for more columns of C and S.
The article is generally reliable and trustworthy, providing an in-depth analysis of the conditions under which nonnegative matrix factorization is partially identifiable. The authors provide a mathematically rigorous theorem of a restricted version of the data-based uniqueness theorem, relying on simple sparsity and algebraic conditions, as well as a geometric interpretation of the restricted DBU theorem that leads to another partial identifiability result in the case r=3. Furthermore, they present sequential partial identifiability results for more columns of C and S.
The article does not appear to be biased or one-sided; it presents both sides equally and does not contain any promotional content or partiality. All claims are supported by evidence from examples provided in the paper, and all possible risks are noted throughout. There are no missing points of consideration or unexplored counterarguments; all relevant information is included in the paper.