US Patent 11775493 Information retrieval system

In various examples there is an information retrieval system which has a memory storing an index of items, each item having one or more features of a plurality of features. The index includes, for each item, an indication of the features of that item; and is configured at least according to the features. The memory stores a plurality of questions about the features of the items. The information retrieval system has a question selector that selects at least one of the questions on the basis of at least an expected information gain of the question with respect to the items. A search component searches the index using answers to the selected questions received from a user.