Unsupervised Relation Disambiguation Using Spectral Clustering 
 This paper presents an unsupervised learning approach to disambiguate various relations between named entities by use of various lexical and syntactic features from the contexts . It works by calculating eigenvectors of an adjacency graph 's Laplacian to recover a submanifold of data from a high dimensionality space and then performing cluster number estimation on the eigenvectors . Experiment results on ACE corpora show that this spectral clustering based approach outperforms the other clustering methods . 