To approximate this objective we use a weighted average of all contexts of u, where contexts are weighted according to their similarity to the given context: where C cu = C u ∪ c (u's corpus contexts plus the given context) and Z is a normalization factor.
is the average fitness of v within the contexts of u, biased to those similar to c. We consider this a contextsensitive similarity score, indicative of the likelihood of v to be a paraphrase of u in context c. 2 we name our in-context representation for a word instance as its paraphrase vector.