@keywords is, a, of.
@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix foaf: <http://xmlns.com/foaf/0.1/>.
@prefix bc: <http://dig.csail.mit.edu/2007/01/camp/data#>.
@prefix contact: <http://www.w3.org/2000/10/swap/pim/contact#>.

@forAll PERSON, MAIL.

{ [is log:semantics of <people.n3> ] log:includes { [] foaf:mbox_sha1sum MAIL }}
=>  { bc:course contact:participant [ foaf:mbox_sha1sum MAIL]  }.