Huh, I'm extremely ignorant of C*-algebras (yet another area where JvN seems to have already been stomping around!) but the expansion between https://en.wikiped

Huh, I'm extremely ignorant of C*-algebras (yet another area where JvN seems to have already been stomping around!) but the expansion between https://en.wikipedia.org/wiki/Graph_C*-algebra#/media/File:Desingularization-1.jpg https://en.wikipedia.org/wiki/Graph_C*-algebra#/media/File:D... and https://en.wikipedia.org/wiki/Graph_C*-algebra#/media/File:Desingularization-2.jpg https://en.wikipedia.org/wiki/Graph_C*-algebra#/media/File:D... really reminds me of Kleene-star expansion from A* to 1|A|AA|AAA|... `*` is an involution in C*, however, and in Kleene `*` is idempotent. Funnily enough, I've written a codegen with an involutive `*`: if one has Dijkstra-style IF...FI and DO...OD constructs in the intermediate language, it's possible to generate reasonable code in such a manner that (merely by patching all the jumps appropriately) one can round trip both IF->DO->IF and DO->IF->DO, with IF->DO corresponding to "star" and DO->IF corresponding to what Conway(?) called the "starth-root". (Just as LISP got LABEL very early and LABELS relatively late, I think a great deal of harm has been done because data processing, from the card era up through early micros, had harsh pragmatic reasons to analyse A* as 1|AA*, yet many things simplify by multiplying cases in the pursuit of symmetry, and instead analysing A* as 1|A|A*A*)