PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • Ghilbert, compared with metamath, adds a number of features most notably definitions (in an attempt, not successful as of 2009, to make it impossible for a poorly constructed definition to render the system inconsistent) and the ability to separate proofs into interfaces and modules.
http://www.w3.org/ns/prov#wasQuotedFrom
  • wikiproofs.org