// if we visit b before c we will miss the value e and if we visit c
// before b we miss the value d.
KnowledgeBase kb = new KnowledgeBase();
ATermAppl a = term( "a" );
ATermAppl b = term( "b" );
ATermAppl c = term( "c" );
ATermAppl d = term( "d" );
ATermAppl e = term( "e" );
ATermAppl p = term( "p" );
ATermAppl r = term( "r" );
ATermAppl s = term( "s" );
kb.addObjectProperty( p );
kb.addObjectProperty( r );
kb.addObjectProperty( s );