Following previous sequence labeling work (Collobert et al., 2011), we introduce a CRF (Lafferty et al., 2001) layer, which has a transition matrix A ∈ R |T |×|T | to give transition scores of adjacent labels.
the score of a label sequence y = y 1:n for a sentence x = x 1:n is calculated as follows: where θ denotes all the parameters and s[y] indicates the dimension of a vector s corresponding to a label y.