void initialiseREXSubPropertyChainOf(REXObjectPropertyExpressionImpl ... roles){
		//		if(roles.length > 3)
		//			System.out.println("incorrect size of role chain!!!");
		Set<REXObjectPropertyExpressionImpl> chains = roles[0].chains.get(roles[1]);
		if(chains == null)
		{
			chains = new HashSet<REXObjectPropertyExpressionImpl>();
			roles[0].chains.put(roles[1], chains);
		}
		chains.add(roles[2]);
	}