To do so, we rely on standard bidirectional long shortterm memory networks (BILSTMs) (Hochreiter and Schmidhuber, 1997;Schuster and Paliwal, 1997).
we denote LSTM θ (w) as the abstraction of a long short-term memory network, that processes an input sentence w=[w 1 , ..., w n ] to generate an output of hidden representations a BILSTM can be seen as BILSTM In this work we will stack two layers of BILSTMs before decoding the output.