# Within-Document Arabic Event Coreference: Challenges, Datasets, Approaches and Future Direction
## 1 Introduction
### Challenges in Arabic Event Coreference  
The Arabic language presents several challenges when it comes to event coreference resolution due to its unique linguistic characteristics. Some of these challenges include then following:  
**Lexical and Morphological Variation**: As shown in Table 3 Arabic has a complex system of inflections and morphological variations that can lead to a variety of surface forms for a given event. As a result of this morphological richness, it may be difficult to identify and link event mentions expressed in different inflected forms. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Arabic** & **English** & **Transliteration** \\ \hline \
\begin{tabular}{c} **Arabic** \\ **Julia crystal** \\ \end{tabular} & Two soldiers were **injured** in
\begin{tabular}{c} **\\ **the attack** \\ \end{tabular} & **Usyeb** jundyan f **ilhujum** \\ \hline \hline \end{tabular}
\end{table} 
Table 1: An Example of annotated events in ACE2005 and TimeML. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Arabic** & **English** & **Transliteration** \\ \hline \begin{tabular}{c} **Arabic crystal** \\ \end{tabular} & Arab condemations & \begin{tabular}{c} **Tawalat al-adanat al-arabiyya** \\ **ill-jarimah al-bashiyah allati** \\ **air-julia crystal** \\ \end{tabular} & \begin{tabular}{c} **Tawalat al-adanat al-arabiyya** \\ **ill-jarimah al-bashiyah allati** \\ **air-julia crystal** \\ \end{tabular} & \begin{tabular}{c} **Tawalat al-bashiyah allati** \\ **air-julia crystal** \\ \end{tabular} \\ \hline \begin{tabular}{c} **Arabic crystal** \\ \end{tabular} & \
\begin{tabular}{c} **Tawalat al-arabiyya** \\ **ill-jarimah al-bashiyah allati** \\ **air-julia crystal** \\ \end{tabular} &
\begin{tabular}{c} **Tawalat al-abanat al-arabiyya** \\ **ill-jarimah al-bashiyah allati** \\ **air-julia crystal** \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: An example of coreferencing events. Consider two sentences: \"A_\",\"S_\",\" ([PERSON] visited the library) and \"A_\",\"S_\" (I visited the library). In the second sentence, the verb form \"A_\",\" is different due to the speaker being first-person singular, making it challenging to link this event to the first sentence. **Dropped Pronouns**: Arabic frequently drops subject pronouns due to its tendency to drop them, making it more difficult to determine the agents of events, which are crucial for resolving coreferences [4]. For instance, in this sentence \"A_\",\"S_\" (Went to school)\" the subject pronoun \"U_\" (I) is dropped, which makes it more difficult to determine the agent of the event. **Pronouns Ambiguity**: Due to the extensive use of pronouns with multiple forms and genders, Arabic pronouns are highly ambiguous, as are other Arabic words. For example, in this sentence: \"A_\",\"S_\",\" (She told her that she loves him)\" both pronouns \"A_\" and \"A_\" refer to different entities. Based on context, it is necessary to disambiguate pronoun referents in order to resolve coreferring events accurately. **Events Ellipses**: These refer to situations where an event is referred to or implied without being explicitly mentioned. Arabic uses events ellipses extensively. In this sentence, \"A_\",\"S_\",\"S_\",\"S_\",\"S_\" (The boy ate an apple and the girl ate an orange)\", the event of eating is referred to twice, but the second time it is implied without being explicitly mentioned in a sentence. By recognizing event ellipsis, the coherence of discourse is enhanced as it aids in resolving coreferring events accurately. **Cultural and Contextual Sensitivity**: The interpretation and resolution of Arabic coreferences may involve a consideration of cultural and contextual factors specific to the Arabic language and its diverse dialects. In order to address these challenges, a deep understanding of Arabic linguistics, advanced natural language processing techniques, and the availability of annotated resources specific to Arabic event coreference resolution are required.