Update README.md

README.md

@@ -25,7 +25,8 @@ This is a copy of the [Multi-XScience](https://huggingface.co/datasets/multi_x_s
 
 - __query__: The `related_work` field of each example
 - __corpus__: The union of all documents in the `train`, `validation` and `test` splits
-- __retriever__: BM25 via [PyTerrier](https://pyterrier.readthedocs.io/en/latest/) with default settings. The number of documents retrieved, `k`, is set as the original number of input documents for each example.
+- __retriever__: BM25 via [PyTerrier](https://pyterrier.readthedocs.io/en/latest/) with default settings
+- __top-k strategy__: `"oracle"`, i.e. the number of documents retrieved, `k`, is set as the original number of input documents for each example
 
 Retrieval results on the `test` set: