@prefix : <#> .
@prefix log: <http://www.w3.org/2000/10/swap/log#> .
@prefix math: <http://www.w3.org/2000/10/swap/math#> .

this log:forAll :at , :na , :sr , :name , :company , :year . 

{ 	:company <http://xmlns.com/foaf/corp#na> :na;
	<http://xmlns.com/foaf/corp#source> :name;
	<http://xmlns.com/foaf/corp#year> :year;
	<http://xmlns.com/foaf/corp#sr> :sr . 
	:na log:notEqualTo "" . 
	:sr log:notEqualTo "" . 
	(:sr :na) math:quotient :at
} 
	log:implies 
{ 

 	:company <http://xmlns.com/foaf/corp#at> :at;
	<http://xmlns.com/foaf/corp#source> :name ;
	<http://xmlns.com/foaf/corp#year> :year  .
} .