# Negation Detection on Mexican Spanish Tweets:
## 2 Related Work
### Spanish Corpora  
Among the Spanish bibliography related to negation annotations, many of them deal with negation in different areas. Table 2 summarizes the Spanish corpora annotated with negation. The first Spanish Corpus annotated with negation in the domain of reviews is the SFU ReviewSP-NEG [18] which consists of 400 reviews extracted from the Ciao.es website. It includes a total of 9455 sentences, with 3022 sentences containing at least one negation structure. This corpus is the Spanish version of SFU ReviewEN-NEG Corpus [15]. In addition, the SFU ReviewSP-NEG [18] is the first Spanish corpus with negation annotations that includes a detailed description of the typology of negation patterns in Spanish, with event and scope annotated.  
There are other Spanish Corpora that deal with negation in different domains: The UAM Spanish Treebank corpus [19] contains 1501 sentences from the newspapers El Pais and Compra Maestra. In total, 160 sentences were identified with negation and syntactically annotated. Similar to the UAM Spanish Treebank corpus [19], there is the NewsCom corpus [20], but, instead of news, the corpus consists of 2955 comments posted in response to 18 news articles from online Spanish newspapers. The news articles cover a variety of nine different topics, two articles per topic. The corpus consists of 4980 sentences, 2247 marked with negation. It is annotated with focus, cue, and scope. In the medical domain, the IxaMed-GS corpus [21] includes 75 electronic health reports with 5410 sentences from the Galdakao Unsansolo Hospital in Spain. In total, 763 entities are syntactically and semantically annotated with negation. The UHU-HUVR corpus [22] consists of 604 clinical reports with 8412 sentences, 1079 with annotated negations from the _Virgen del Rocio_ Hospital in Spain.  
In addition, the IULA Spanish Clinical corpus is in the medical domain with clinical reports [23] from a hospital in Barcelona. It contains 300 clinical reports with 3194 sentences, being 1093 tagged with negation cues. In this work, the authors created their own guidelines to elaborate the corpus. Another clinical negation corpus in Spanish is the NUBES corpus [24] with 29,682 sentences from anonymized health records sup  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Corpus** & **Year** & **Domain** & **Scope** & **Event** & **Number of Sentences** & **Annotated Negations** \\ \hline BioInfer & 2007 & Medical & Yes & No & 1100 & 163 \\ BioScope & 2010 & Medical & Yes & No & 20,924 & 2720 \\ NegDDI-DrugBank & 2013 & Medical & Yes & No & 5806 & 1399 \\ NEG-DrugDDI & 2014 & Medical & Yes & No & 6648 & 1448 \\ PropBank & 2011 & Journal & No & No & 3779 & 3993 \\ SFU Opinion and & 2019 & Journal & Yes & No & 1043 (comments) & 1397(negation cues) \\ Products Review & 2010 & Review & No & No & 2111 & 679 \\ SFU ReviewEN-NEG & 2012 & Review & Yes & No & 17,263 & 3017 \\ Conan Doyle-neg & 2012 & Literature & Yes & Yes & 4423 & 995 \\ Deep Tutor Negation & 2016 & Educational & Yes & No & 27,785(response) & 2603 (responses) \\ \hline \hline \end{tabular}
\end{table}
Table 1: English corpora annotated with negation.  
plied by a Spanish private hospital. It contains 7567 sentences with negation, annotated with scope, event, and cue. Most of the corpora cited here were described in detail by [PERSON] et al. (2018).