To accept two arguments, i.e., input sentence X and style id k, we can directly concatenate the one-hot representation of style id one hot(k) and the embedding vector h T obtained by bi-LSTM encoder and then feed the concatenated vector [one hot(k), h T ] instead of h T into the decoder model without changing anything else.
there is no theoretical guarantee that the output sentence generated by the decoder is strongly correlated to the style id input one hot(k).