A Generalized Framework for Network Component Analysis
IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB)
NP-completeness results for edge modification problems
Discrete Applied Mathematics - Special issue: Traces of the Latin American conference on combinatorics, graphs and applications: a selection of papers from LACGA 2004, Santiago, Chile
Random Structures & Algorithms
Hardness of edge-modification problems
Theoretical Computer Science
Document clustering using nonnegative matrix factorization
Information Processing and Management: an International Journal
Structural Identifiability in Low-Rank Matrix Factorization
Algorithmica - Special Issue: Computation and Combinatorial Optimization; Guest Editors: Xiaodong Hu and Jie Wang
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A bipartite graph G=(L,R;E) with at least one edge is said to be identifiable if for every vertex v@?L, the subgraph induced by its non-neighbors has a matching of cardinality |L|-1. This definition arises in the context of low-rank matrix factorization and is motivated by signal processing applications. In this paper, we study the resilience of identifiability with respect to edge additions, edge deletions and edge modifications. These can all be seen as measures of evaluating how strongly a bipartite graph possesses the identifiability property. On the one hand, we show that computing the resilience of this non-monotone property can be done in polynomial time for edge additions or edge modifications. On the other hand, for edge deletions this is an NP-complete problem. Our polynomial results are based on polynomial algorithms for computing the surplus of a bipartite graph G and finding a tight set in G, which might be of independent interest. We also deal with some complexity results for the optimization problem related to the isolation of a smallest set J@?L that, together with all vertices with neighbors only in J, induces an identifiable subgraph. We obtain an APX-hardness result for the problem and identify some polynomially solvable cases.