Closed awodey closed 11 years ago
Isn't this 4.4.9, except that it doesn't say the words "polynomial functor"?
the proof of 4.4.9 is what I added last night. today I realized that it uses the polynomial point of view, which doesn't come up previously.
Mentioning the polynomial PoV sounds good to me.
I'll patch in something, but someone else should then read it for coherence with the rest.
I reorganized it a bit, to start with nat-algebras as a lead-in and then define the polynomial endofunctor and its algebras just before proving the theorem. I think it reads better this way, what do you think?
yes, more clear this way.
Chapter 4 doesn't use the idea of W-types as initial algebras of polynomial functors! Unless someone else is willing to do it, I propose to add a bit on this point of view in section 4.4 -- it will mostly be lifted from our LICS paper.