User blog comment:Googleaarex/Unlimitable Ordinals/@comment-25418284-20130823215256/@comment-5150073-20130825103444

There could be even stronger notations with 3 rules, even though it's unknown. We have to run through all notations with 3 rules, and certain form have to be specified for all them. For example, what is the rule itself? I can define # symbol as "# indicates the rest of an expression", will it be counted as the rule?