docs: public boolean isUnifiableWith(SyntacticCategory other) {
      Map<Integer, String> myAssignedVariables = Maps.newHashMap();
      Map<Integer, String> otherAssignedVariables = Maps.newHashMap();
      Map<Integer, Integer> variableRelabeling = Maps.newHashMap();
  
      // System.err.println("unifying: " + this + " " + other);
      return isUnifiableWith(other, myAssignedVariables, otherAssignedVariables, variableRelabeling); 
    }