Our experiments with Support Vector Machines on question/answer classification show that our kernels can be used to greatly improve system accuracy.
u is a subsequence of s if there is a sequence of indexes is the distance between the first and last character of the subsequence u in The set of all substrings of a text corpus forms a feature space denoted by F = {u 1 , u 2 , ..} ⊂ Σ * .