  Unsupervised text style transfer aims at training a generative model that can
alter the style of the input sentence while preserving its content without
using any parallel data. In this paper, we employ powerful pre-trained large
language models and present a new prefix-tuning-based method for unsupervised
text style transfer. We construct three different kinds of prefixes, i.e.,
\textit{shared prefix, style prefix}, and \textit{content prefix}, to encode
task-specific information, target style, and the content information of the
input sentence, respectively. Compared to embeddings used by previous works,
the proposed prefixes can provide richer information for the model.
Furthermore, we adopt a recursive way of using language models in the process
of style transfer. This strategy provides a more effective way for the
interactions between the input sentence and GPT-2, helps the model construct
more informative prefixes, and thus, helps improve the performance. Evaluations
on the well-known datasets show that our method outperforms the
state-of-the-art baselines. Results, analysis of ablation studies, and
subjective evaluations from humans are also provided for a deeper understanding
of the proposed method.
