---
dataset_info:
- config_name: full
  features:
  - name: doc_key
    dtype: string
  - name: gutenberg_key
    dtype: string
  - name: sentences
    sequence:
      sequence: string
  - name: clusters
    sequence:
      sequence:
        sequence: int64
  - name: characters
    list:
    - name: name
      dtype: string
    - name: mentions
      sequence:
        sequence: int64
  splits:
  - name: train
    num_bytes: 118643409
    num_examples: 45
  - name: validation
    num_bytes: 5893208
    num_examples: 5
  - name: test
    num_bytes: 2732407
    num_examples: 3
  download_size: 317560335
  dataset_size: 127269024
- config_name: splitted
  features:
  - name: doc_key
    dtype: string
  - name: gutenberg_key
    dtype: string
  - name: sentences
    sequence:
      sequence: string
  - name: clusters
    sequence:
      sequence:
        sequence: int64
  - name: characters
    list:
    - name: name
      dtype: string
    - name: mentions
      sequence:
        sequence: int64
  splits:
  - name: train
    num_bytes: 118849212
    num_examples: 7544
  - name: validation
    num_bytes: 5905814
    num_examples: 398
  - name: test
    num_bytes: 2758250
    num_examples: 152
  download_size: 317560335
  dataset_size: 127513276
language:
- en
pretty_name: BOOKCOREF
size_categories:
- 10M<n<100M
tags:
- coreference-resolution
license: cc-by-sa-4.0
---


<div align="center">
  <img src="assets/bookcoref.png" width="700">
</div>
<!-- Aggiungi nome degli autori, ACL 2025, link  -->
This repository contains the <span style="font-variant: small-caps;">BookCoref</span> dataset, introduced in the paper "<span style="font-variant: small-caps;">BookCoref</span>: Coreference Resolution at Book Scale" by [Martinelli et al., 2025]().


We release both the manually-annotated `test` split (<span style="font-variant: small-caps;">BookCoref</span><sub>gold</sub>) and the pipeline-generated `train` and `validation` splits (<span style="font-variant: small-caps;">BookCoref</span><sub>silver</sub>).
In order to enable the replication of our results, we also release the splitted version of each split, available by adding the suffix `_splitted` to each split name.
As specified in the paper, this version is obtained through chunking the text into contiguous windows of 1500 tokens, retaining the coreference clusters of each window.

## 📚 Quickstart

Simply load the dataset through Huggingface's `datasets` library:

```python
from datasets import load_dataset

bookcoref = load_dataset("sapienzanlp/bookcoref")
```

## ℹ️ Data format

<span style="font-variant: small-caps;">BookCoref</span> is a collection of annotated books. 
Each item contains the annotations of one book following the structure of OntoNotes:

```python
{
  doc_id: "pride_and_prejudice_142", # (str) i.e., id of document 
  sentences: [["Pride", "and", "Prejudice", "."], ["Begin", ...], ...], # list[list[str]] i.e., list of word-tokenized sentences
  clusters: [[[0,0], [3,5]], [[4,9]...], ...], # list[list[list[int]]] i.e., list of clusters' mention offsets
  characters: [
    {
      name: "Mr.Bennet", 
      cluster: [[0,0], ...],
    },
    {
      name: "Mr. Darcy",
      cluster: [[5,7], ...],
    }
  ] # list[character], list of characters objects with name and his mentions offsets, i,e., dict(name: str, cluster: list[list[int]])
}
```
<!-- Add description of fields in example, maybe OntoNotes format is not enough -->
We also include information on character names, which is not exploited in traditional coreference settings, but can be useful in future works.

## 📊 Dataset statistics

<span style="font-variant: small-caps;">BookCoref</span> has distinctly book-scale characteristics, as summarized in the following table:

<!-- chage to markdown table  -->
<div align="center">
  <img src="https://cdn-uploads.huggingface.co/production/uploads/64f85270ceabf1e6fc524bb8/DgYU_2yKlZuwDTV-duGWh.png" width=1000/>
</div>

## 🖋️ Cite this work

This work has been published at ACL 2025 (main conference). If you use any artifact of this dataset, please consider citing our paper as follows:

```bibtex
@inproceedings{martinelli-etal-2025-bookcoref,
    title = "{BookCoref}: Coreference Resolution at Book Scale",
    author = "Martinelli, Giuliano  and
      Bonomo, Tommaso  and
      Huguet Cabot, Pere-Llu{\'\i}s  and
      Navigli, Roberto",
    booktitle = "Proceedings of the 63nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)",
    month = jul,
    year = "2025",
    address = "Vienna, Austria",
    publisher = "Association for Computational Linguistics",
}
```


## ©️ License information

All the annotations provided by this repository are licensed under the [Creative Commons Attribution Share Alike 4.0](https://creativecommons.org/licenses/by-nc/4.0/) license. The tokenized text of books is a modification of books from Project Gutenberg, following [their license](https://www.gutenberg.org/policy/license.html).