docs: @Override
  	public boolean isConflicting(Activity[] peak) {		
  		if (peak.length != 2) return false;
  		((SymbolicVariableActivity)peak[0].getVariable()).getSymbolicVariable().getDomain();
  //		Vector<String> intersection = new Vector<String>(Arrays.asList(((SymbolicDomain)peak[0].getSymbolicVariable().getDomain()).getSymbols()));
  //		intersection.retainAll(Arrays.asList(((SymbolicDomain)peak[1].getSymbolicVariable().getDomain()).getSymbols()));
  		Vector<String> intersection = new Vector<String>(Arrays.asList(((SymbolicVariableActivity)peak[0].getVariable()).getSymbolicVariable().getSymbols()));
  		intersection.retainAll(Arrays.asList(((SymbolicVariableActivity)peak[1].getVariable()).getSymbolicVariable().getSymbols()));
  		return intersection.isEmpty(); // if the intersection is null these variables do not share symbols and therefore can not co-exist
  	}