@prefix log: <http://www.w3.org/2000/10/swap/log.n3#> .
@prefix dc: <http://purl.org/dc/elements/1.1/> .
@prefix stuff: <friends.n3#> .

<> log:forAll <#a> , <#b> , <#c> .

{ <#a> stuff:coWrote <#b> . <#c> stuff:coWrote <#b> . }
log:implies 
{ <#a> stuff:collaboratedWith <#c> . } .