Necessity of the a b constructor in the Richter operator
Ascertain whether the binary constructor a b in the Richter operator is necessary; specifically, determine if Richterian notation systems and associated coding results can be obtained without including the a b constructor.
References
The role of $a b$ is rather technical, and the author does not know about its necessity. Richter also mentioned in that he does not know if the $$ operator is necessary.
— Proof-theoretic dilator and intermediate pointclasses
(2501.11220 - Jeon, 20 Jan 2025) in Appendix: Iterated hyperjumps, Subsection "Ordinal notation system"