Formally, when a word x i is shifted to the stack at time step k, its representation is computed as: Finally, the state of the system p k is the concatenation of the states of buffer, stack and action history: We employ the greedy strategy to maximize the log-likelihood of the local action classifier in (1).
let z ik denote the k-th action for the i-th sentence, the loss function with 2 norm is: where λ is the 2 coefficient.