A challenge with the [[Positive_Sentence_Harverting?]] phase is that the Training Cases may lead to the identification of sentences that contain a different relation than the one sought. One reason for this outcome is that the entities in the training cases may be ambiguous. For the PEOPLE entity type, for example, the name John Smith will match many individuals. If IsSiblingTo() is the Semantic Relation sought then having a training case such as: (John Smith,Jane Smith) will match many sentences that refer to different people than the ones intended. John Smith and Jane Smith may instead be in a IsParentTo() relation, or may simply be acquaintences with the same last name... However, this problem is likely not a significant one in that it is likely that most of training cases will uniquely identify a sentence with a correct relation. For the pair (Alan Turing,John Turing) for example, only correct sentences would be retrieved (if any). ... This problem could be alleviated by [[Multi-document_Coreference_Resolution?]].
A challenge with the [[Positive_Sentence_Harverting?]] phase is that the training cases given will not lead to the identification of any sentences. For the pair (Alan Turing,John Turing) for example, a Google search found no sentences with both names on them. ... This problem could be alleviated by Discourse-level Analysis which may for example