User blog comment:Ubersketch/CNFlex/@comment-35470197-20190908003106/@comment-35470197-20190908024404

> He explicitly stated that the symbols are ordered lexicographically. That's a total order. So what's the problem? The order itself defines the ordinals.

I meant, his rule a+b -> abC is ill-defined because an ordinal is not uniquely expressed as a sum. The handling of formal strings (expressions) is good. The problem is the handling of ordinals. In order to distinguish ordinals and expressions, this kind of well-definedness is good to study.