About: http://webisa.webdatacommons.org/131019846

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	All these algorithms are based on rewriting join trees based on the algebraic properties of the join operator such as commutativity and associativity in order to generate alternative query trees.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com