Unsupervised Spectral Learning of WCFG as Low-rank Matrix Completion
Raphaël Bailly, Xavier Carreras, Franco M. Luque, Ariadna Quattoni · 2013
We derive a spectral method for unsupervised learning of Weighted Context Free Grammars.We frame WCFG induction as finding a Hankel matrix that has low rank and is linearly constrained to represent a function computed by inside-outside recursions.The proposed algorithm picks the grammar that agrees with a sample and is the simplest with respect to the nuclear norm of the Hankel matrix.