This issue is to track the contribution of the Semantic Knowledge Graph Solr Plugin (request handler), which exposes a graph-like interface for discovering and traversing significant relationships between entities within an inverted index.
This data model has been described in the following research paper: The Semantic Knowledge Graph: A compact, auto-generated model for real-time traversal and ranking of any relationship within a domain, as well as in presentations I gave in October 2015 at Lucene/Solr Revolution and November 2015 at the Bay Area Search Meetup.
The source code for this project is currently available at https://github.com/careerbuilder/semantic-knowledge-graph, and the folks at CareerBuilder (where this was built) have given me the go-ahead to now contribute this back to the Apache Solr Project, as well.
Check out the Github repository, research paper, or presentations for a more detailed description of this contribution. Initial patch coming soon.