Reasoning in Vector Space: An Exploratory Study of Question Answering
This work addresses the problem of interpretable reasoning in AI for researchers, though it is incremental in applying TPR to existing datasets.
The paper tackled the challenge of complex reasoning in question answering by proposing vector space models based on Tensor Product Representation for knowledge encoding and logical inference, achieving near-perfect accuracy on difficult bAbI tasks like positional reasoning and path finding.
Question answering tasks have shown remarkable progress with distributed vector representation. In this paper, we investigate the recently proposed Facebook bAbI tasks which consist of twenty different categories of questions that require complex reasoning. Because the previous work on bAbI are all end-to-end models, errors could come from either an imperfect understanding of semantics or in certain steps of the reasoning. For clearer analysis, we propose two vector space models inspired by Tensor Product Representation (TPR) to perform knowledge encoding and logical reasoning based on common-sense inference. They together achieve near-perfect accuracy on all categories including positional reasoning and path finding that have proved difficult for most of the previous approaches. We hypothesize that the difficulties in these categories are due to the multi-relations in contrast to uni-relational characteristic of other categories. Our exploration sheds light on designing more sophisticated dataset and moving one step toward integrating transparent and interpretable formalism of TPR into existing learning paradigms.