About: http://webisa.webdatacommons.org/422274624

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	Subtracting intervals is not too hard, but it is a bit tedious to work out all the cases if you track whether endpoints are open or closed.
http://www.w3.org/ns/prov#wasQuotedFrom	mathoverflow.net