public TypeSystemImpl() {
// Changed numbering to start at 1. Hope this doesn't break
// anything. If it does, I know who's fault it is...
this.typeNameST = new SymbolTable(1);
this.featureNameST = new SymbolTable(1);
this.featureMap = new StringToIntMap();
// In each Vector, add null as first element, since we start
// counting at 1.
this.tree = new ArrayList<IntVector>();
this.tree.add(null);
this.subsumes = new ArrayList<BitSet>();