  In this paper, we study the product title summarization problem in E-commerce
applications for display on mobile devices. Comparing with conventional
sentence summarization, product title summarization has some extra and
essential constraints. For example, factual errors or loss of the key
information are intolerable for E-commerce applications. Therefore, we abstract
two more constraints for product title summarization: (i) do not introduce
irrelevant information; (ii) retain the key information (e.g., brand name and
commodity name). To address these issues, we propose a novel multi-source
pointer network by adding a new knowledge encoder for pointer network. The
first constraint is handled by pointer mechanism. For the second constraint, we
restore the key information by copying words from the knowledge encoder with
the help of the soft gating mechanism. For evaluation, we build a large
collection of real-world product titles along with human-written short titles.
Experimental results demonstrate that our model significantly outperforms the
other baselines. Finally, online deployment of our proposed model has yielded a
significant business impact, as measured by the click-through rate.
