User blog comment:Edwin Shade/Understanding The Infinite/@comment-32213734-20171110205605/@comment-32213734-20171110222037

Deedlit11, greetings! I read some of your blogs, very interesting, especially about collapsing functions...

So, you are right, I think so too, two rules simpler than three. When I read this blog, I could not realize why common fixed points, not just fixed points. I was wondering, is any difference between ζ defined through fixed and through common fixed points since Edwin Shade started to talk about common fixed points long before φ(ω,0). Then I checked Veblen function article, and there were common fixed points too. Only a bit later I realized that common fixed points are about limit ordinals. So, I think, it actually would be more clear to readers first to explain rule for successor ordinals, then, beginning from φ(ω,0), explain rule for limit ordinals and then mention that this is actually a single rule.