Distributed Tree Kernels
  In this paper, we propose the distributed tree kernels (DTK) as a novel method to reduce time and space complexity of tree kernels. Using a linear complexity algorithm to compute vectors for trees, we embed feature spaces of tree fragments in low-dimensional spaces where the kernel computation is directly done with dot product. We show that DTKs are faster, correlate with tree kernels, and obtain a statistically similar performance in two natural language processing tasks. 
Fabio Massimo Zanzotto (University of Rome-Tor Vergata), Lorenzo   Dell'Arciprete (University of Rome-Tor Vergata)
cs.LG stat.ML