Unsupervised Spectral Learning of WCFG as Low-rank Matrix Completion

Raphaël Bailly, Xavier Carreras, Franco M. Luque, Ariadna Quattoni

Abstract:

We derive a spectral method for unsupervised
learning ofWeighted 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.