0b4ac2b0_earch___the_Feature_Smackdown___Solr_4_7_0
[Feature] Negative boosting [Solr 4.7.0] 
but awkward. Involves positively boosting the inverse set of negatively-boosted documents.
Apache Solr vs ElasticSearch - the Feature Smackdown!
Solr 4.7.0